Originally Posted by jibber

A few people mentioned radiohead, and while they are definitely a good example, I think they're similar to the chilli peppers in that it has been more of an ongoing evolution as opposed to a sudden a drastic change between albums.

Smashing pumpkins is an interesting one. Their evolution has been more of a sporadic, wierd, jerky transition from alt-rock, to more "experimental" sounding accoustic-electronic-rock-ish-mishmash, to their stuff now thats a lot more uniformly hard rock than any other album. Oh, and don't forget all the member's forays into solo work thrown in there as well.