What are the different ways of saying dead?

(go to/be in)Abraham's bosom
an awfully big adventure - J.M Barrie, Peter Pan (Ceiridwen's favourite!)
at the end of one's rope
answer the last call
awake to life immortal
basting the formaldehyde turkey - chefs' euphemism
(the) big jump - cowboy slang
(was) beamed up - Star Trek reference
(the) big sleep
bite it
bite the big one
bite the biscuit
bite the dust
bless the world with one's heels - hanging reference
(the) bosom of the Father and his God - Thomas Gray
bought a pine condo
bought the disk farm - computer geek euphemism
bought his lunch
buy the box - coffin
breathe one's last
buy the farm
cached in his chips - computer geek euphemism
cashed in
cash in your chips - another reference to viewing life as a loan
checked out
cash out
climb the Golden Stair
coiled up his ropes
collapsed his/her outline - specific to technical writers
condition non-conducive to life - terminally ill
cooking for the Kennedys - chefs' euphemism
croaked
crossing the bar - Tennyson
crossing the river
cross on the Stygian ferry
cross the Great Divide
(the) crown of life - Edward Young
curtains - theatre reference
dance on air - hanging
dangle in the sheriff's picture frame - hanging
deanimate
debt we all must pay - Euripides
deleted from the BOM - specific to technical writers
disassemble - Short Circuit (late 80's movie)
disincorporate - martian suicide, in Heinlein's "Stranger in a Strange Land"
donating the liver paté - chefs' euphemism
done like dinner
(the) downward path - Horace
(the) dread abode - Thomas Gray
(that) dreamless sleep - Byron
(the) empty vessel
end of the line
(the) eternal yawn
exported to a flat file - computer geek euphemism
face-planting the meringue (???) - chefs' euphemism
fade away
feed the fishes - returning to nature
(that) fell sergeant - personification of Death by Shakespeare
fettucine al dead-o - chefs' euphemism
filleting the soul - chefs' euphemism
flatline
formatted with black borders - specific to technical writers
for whom the bell tolls - A reference to a prose work by John Donne (1573-1631) entitled 'Meditation 17' "...therefore never send to know for whom the bell tolls; it tolls for thee." ...Thanks Julie!
freeing the spirit
(be) gathered to one's fathers
gate of life - St. Bernard
get your halo
gibbed - Dying in an explosive manner in video games like Quake... you leave giblets, or "gibs" for short, laying around
give an obolus to Charon
give up the ghost
go for a burton - British
go home feet first
go home in a box - military, esp. during WW2
goin' to a dance pawty wit' Gawd!
going into the fertilizer business
gone to the big glass house in the sky - computer geek euphemism
go the way of all earth - Biblical
go the way of all flesh
go to a necktie party - hanging
go to a necktie social - hanging
go to meet one's maker
go to one's just reward
go to one's last home
go to one's last account
go to one's rest
go to the happy hunting ground
go to the last roundup - cowboy expression
go west - The sun setting in the west was tied to death in some cultures (esp. Egyptian). Also a pioneer expression.
(that) grim ferryman - personification of Death by Shakespeare
(the) great leveller
had his/her 80-column card punched - computer geek euphemism
(the) Hamlet sleep - Thomas Gray
hand in one's chips
hang up your tack - cowboy expression
has reservations at the Chateau Eternity - chefs' euphemism
Hell's grim tyrant - personification of Death by Pope
his number's up
immortally challenged
(the/th') inevitable hour - Thomas Gray
information superhighway roadkill - computer geek euphemism
inspired a new warning message - specific to technical writers
in the sweet hereafter
it's Taps - military
join one's ancestors
join the angels
join the majority - Oddly enough, this isn't accurate anymore... there are more people living now than have ever lived.
(the) journey's end - Shakespeare
Just Add Maggots - chefs' euphemism
kick the bit bucket - computer geek euphemism
kick the bucket - hanging
kick the can - hanging
kicked the oxygen habit
kind Nature's signal of retreat - Samuel Johnson
(the) king of terrors - Biblical personification of death
kiss the dust
kneel at the big gates - Catholic reference to the gates of Heaven
(get) knocked off - gangster speak
(the) latter end - Biblical
launched into eternity
left the building
"a little folding of the hands to sleep" - Biblical
(a) little sleep
(a) little slumber
living-challenged
living-impaired
lost in translation - specific to technical writers
mailed in his/her warranty card - specific to technical writers
marinating in soil and worms - chefs' euphemism
meat
meet one's maker
meet the reaper
moved into upper management - specific to technical writers
negative patient care outcome - so very PC
never-ending trip
(the) Notorious D.O.A. - became a joke after the Notorious B.I.G.'s death
off the record
on one's last legs - dying
on the Hell Express/express elevator to Hell
on the road to nowhere
(the) pale priest of the mute people - personification of Death by R. Browning
pass over Jordan - Biblical
passed on
(get) pasted - refers to a violent death
pay one's debt to nature - many cultures see life as a loan
pay the piper
peasant under grass - chefs' euphemism
peg out - cribbage reference
permanently out of print - specific to technical writerspermasleep
picking up your harp
pop off the hooks - somewhat irreverent allusion to the Crucifixion and de-nailing/taking down of Jesus Christ's body after his death
printed white on white - specific to technical writers
promoted to Subterranean Truffle Inspector - chefs' euphemism
pull the plug - euthanasia
pushing up daisies
pushin' up parsley - chefs' euphemism
put in the crisper - chefs' euphemism
put on immortality
remaindered - specific to technical writers
reformatted by God - computer geek euphemism
retroactive abortion
ride the lightning - Get executed in the electric chair
rung down the curtain and joined the Choir Invisible!
(the) seamouth of mortality - Robinson Jeffers
sampling the French Onion Soup with a salmonella spoon (???) - chefs' euphemism
sent to the dirt archives - computer geek euphemism
shed the mortal coil
shit the bed
shuffle off this mortal coil - Shakespeare
singing with the angels
six feet under
sleep with the fishes - gangster speak
(the) sleeping partner of life - Horace Stern
sleeping with the quiches - chefs' euphemism
slip one's cable
slowly cooling to room temperature - chefs' euphemism
(get) smeared - refers to a violent death
snuff it
sowing the Elysian Fields - Greek reference to the resting place of heroes
(get) sporked off - Kind of an onomatopoeia. Spork!
step onto one's last bus
street pizza - car accident victims
struck out by the Big Blue Pencil - specific to technical writers
sun one's moccasins
take a dirt nap
take an earth bath
taken out of production - computer geek euphemism
take the last count
"...that fell arrest which summons the all without bail" - Shakespeare
that good night - "Do not go gentle into that good night", Sir Dylan Thomas
(get) toasted
toes up - there's a visual that goes with it, you have to put your arms out stiffly at a 45 degree angle, kind of like a two-armed Nazi salute
toss in one's alley - Australian. Reference to marbles.
tribute due unto nature - Laurence Stern
turning up daisies
turn one's face to the wall - The final gesture of acceptance. "He turned his face to the wall / And prayed unto the Lord." 2 Kings 22:2
turn up one's toes
(the) undiscovered country - Hamlet
visiting Davy Jones' locker
walked the plank
wear a glass necklace - An old reference to car accidents, in which the victim's head would go through the windshield.
wearing a columbian necktie - Get your throat cut & tongue pulled through. Yum.
wearing cement overshoes - gangster execution method
wearing concrete galoshes - gangster execution method
wearing concrete shoes - gangster execution method
went on-line - specific to technical writers
(get) whacked - gangster speak
widowed and orphaned - specific to technical writers
worm food

As once was said in a famous monty python sketch...

'E's a stiff! Bereft of life, 'e rests in peace! If you hadn't nailed 'im to the perch 'e'd be pushing up the daisies!

'Is metabolic processes are now 'istory! 'E's off the twig!

'E's kicked the bucket, 'e's shuffled off 'is mortal coil, run down the curtain and joined the bleedin' choir invisibile!!

Died, passed on, kicked the bucket, bought the farm, wearing wings, eliminated from the gene pool, croaked, 6 feet under, pushing up daisies, went to the other side.

deceased
put down
put to sleep
down for the count
whacked
hit
murdered
slaughtered
Died
in a better place
passed on
hes just sleeping
a broken pulse
6 feet under
with grandpa now
at th pearly gates
awaiting judgement
sorry hunny, charlie "ran away"
pushing up daisies
hes up there
taking a nap
this list has been done in

Assumed room temperature
Assumed ambient temperature

bite the curb

leaving this world....among the others mentionned by tjaherton.

In Scotland we sometimes say Broon breed as in brown bread, it is rymeing slang

brown bread
snuffed it
kicked the proverbial bucket
expired
passed away
"breathes not the foul air of this cruel world any longer"
pushing up daisies
big sleep
eternal rest
86'ed
permanently bummed
gonner
croaked
whacked
offed

can no longer breathe
rip
10 feet below...
i don't think i can beat Mr. McClister though!