The answer is “any” but if bass is what you really want to play you might be better off not learning guitar first at all. With the possible exception of Jazz, the art of bass is to work with the drums to provide a solid foundation for the music. There is no shortage of wanna be “guitar heroes” but a great rhythm section is rare and priceless. It isn’t an accident that Double Trouble is still together and in demand 16 years after Stevie Ray Vaughn’s death. A bass player that knows how to stay “in the pocket” and tailor the bass part to the song will always have work. The problem I’ve had with bass players that started on guitar, particularly if they play lead guitar, is that they tend to want to play too much. The art of bass is to play just enough to fill in the sound and keep the song rhythmically interesting. A great rhythm section can make a mediocre guitar player sound decent. A bass player that habitually tries to compete with lead instruments makes the music too busy. Some of the very best bass players I have worked with also play drums. That should tell you something. Many also play guitar but consider bass and drums to be their main instrument. If you want to learn both, you might be better off learning bass first and then learning guitar. Since bass is rarely a solo instrument, most bass players learn ensemble playing from the first note. To be any good a bass player must play perfectly with the drummer so bass players often learn by practicing with a metronome or drum machine. Being able to play “in the pocket” against a rhythm source will make anyone a better guitar player. In a nutshell, if you want to play bass, play bass. I play both and I think that it would have been far easier to go from bass to guitar than the other way around. (Which is how I learned.) Hope this helps! JMAC

I actually tried guitar first and when I found out it wasn't my thing, I put it down and picked up a bass. But every now and then I find myself playing with my acoustic guitar and usually use it to create new riffs and lines

I would also like to add that it's very good idea to have a working knowledge of piano and drums. In fact, it's probably more impoortant that learning guitar in the long run.

You don't have to learn guitar first. If you want to play bass, then start off learning the bass. It just happens that a lot of people start out with guitar and then switch to bass because they decided they'd rather play the bass. But you don't have to start with guitar. If you insist on learning guitar first, then I would recommend learning whatever style of music that you intend to play on the bass. Technicaly, the bass player in a band works closely with the drummer to lay down a solid foundation to the song, so it wouldn't heart to learn a little about drumming either! Drummers go crazy if the bass player is not sync'd to their beat!

I just went from keyboard to the bass...