As a guitarist (well, more of a guitarist than anything else) who plays bass occasionally, I go for flatwound too
I consider myself more a musician who has probably got paid more to play bass than anything else. And the reason is because I have a good idea of what the bass player is supposed to
do in a band, where they sit in the mix... there have been occasional bands where the bass player was out front with good success - the Who, of course, and in my opinion the only thing that held the Red Hot Chili Peppers' sound together was Flea, the rest of the band were sloppy, out of tune, perhaps even... high on drugs!
Gasp! When Stanley Clarke, a brilliant technician, left Return to Forever and went out on his own star turn, his band had to hire a bass player to play the bass parts because Stanley was out front, playing his "piccolo bass" - a four-string instrument tuned an octave higher, you figure it out. Obviously, bass players are going to like something like this:
http://www.youtube.com/watch?v=H3tLLzSGd2o&feature=related
But if you played that on another instrument it would sound like nonsense, as it isn't very good
music. A good bass player can do more to make a band sound good than the soloists, really - you get to push the beat around, as does the drummer. But a bass player who grew up thinking that Pastorius and Clarke were the bomb is going to be a pain in the ass.