Terrible stereotype. It's like saying all witches are ugly crones.

Not necessarily dance, but many Wiccans worship skyclad (which is naked) in their covens - and one could say it is in the moonlight, since most covens meet on the Esbats which is the full moon and the new moon. This is done so that there is nothing between you and the God and Goddess - it's kind of like you're presenting yourself exactly as you are; no holds barred; no facade of clothing or anything else to hide behind; it's just you, your closest friends, and the All. (Worshiping could include "dance" depending on the ritual.) However, practicing skyclad only occurs within covens that have PERFECT TRUST with one another - and nowadays, this isn't as common as it used to be (so, by result, most choose to worship fully clothed). As for gathering herbs, I think it's safe to say that most (if not all) Wiccans gather herbs. Wicca places a strong emphasis on herbalism and the power (magically and medicinally) of various herbs. Depending on one's tradition and the type of witchcraft they practice/specify in, gathering herbs at different times (i.e. Full Moon, on a certain Sabbat, when the Sun is at it's highest/lowest, etc.) is sometimes believed to make the herbs more potent. In answer to your last question, I typically practice clothed, but that doesn't mean that I would never consider doing it skyclad. It would just depend on the ritual I was doing and how I felt about it at the time (although I would most likely do it alone since I'm a solitary Wiccan and don't belong to a coven). I also gather herbs at various special times throughout the year like the ones I mentioned above (and buy from metaphysical shops for what I cannot gather on my own). So, in short, yes I would.

I am Wiccan, I have gathered herbs, and I have danced naked in the moonlight. I would like to do more dancing naked in the moonlight, but it's hard to find places you can do that in the Land of the Free.