with you there! You can slap and pop on a guitar but only on the low strings and it doesn't sound so cool. A really good bass player can sound like they have a whole drum kit at their fingertips as well as a tuned instrument. personally I dig trebly bass with lots of percussive stuff and I also dig the warm soft slidy tones of fretless bass.
My favourite bass solo is possibly a Billy Sheehan one from the rush Tribute album "working man" on the cover of La Villa Strangiato. Geddy lee (from Rush) has written tons of top bass melodies. Of other mainstream rock bands the only other frequently bass lead group I can think of isPrimus, Les Claypool kicks swathes of ass. I don't really like them but Level 42's bassist Mark King is an absolutely awesome bass player. Another fave of mine is Stu Hamm who has written his own solo stuff as well as playing with Satriani.