the great thing about psychedelic music is it's still going strong, they just keep the drugs on the down-low these days.
here's some great modern psychedelic rock bands:
smashing pumpkins (gish, siamese dream, pieces escariot)
tool (they get more so with each album. lateralus is the most psychedelic)
radiohead (mostly ok computer and everything after)
janes addicition (more so the earlier stuff)
sigur ros
glassjaw (cross between psychedelic and post-hardcore)
spongle (more trip-hop style stuff)
bjork (not really rock but still very psychedelic, especially the last couple albums)
incubus
hum
modest mouse
john vanderslice
the important thing to remember here is that psychedelic music isn't made up of a certain "sound" the way other genres are. rather, it is the application of a certain sensibility (the psychedelic sensibility, obviously) to the musical format of choice. so while pearl jam and smashing pumpkins are both "alternative" bands, pearl jam is not psychedelic while smashing pumpkins is. if you're "experienced" you learn to pick up on it really quickly, especially if you're also a musician. also, don't confuse psychedelic rock with stoner rock. modern stoner rock bands include deftones and queens of the stone age. the important thing here is that psychedelic rock doesn't have to be that aging-hippy jam-band cliche. personally i hate that crap and i think the pumpkin's siamese dream is actually a lot more psychedelic than say, phish.
these bands are not psychedelic:
linkin park and crew
staind and crew
anything punk
almost anything emo
weezer
red hot chili peppers (except for one hot minute because of dave navarro)
the vast majority of metal
new wave
not to say that metal or new wave couldn't become psychedelic if you wanted to, it's just that most people who would be in those bands wouldn't take them cause they're for hippies (which would be either wimpy, uncool, or both, depending on who you talk to).
edit: i'm not passing judgment on the non-psychedelic bands. i actually like a lot of emo, and weezer, and they've been big influences on me as a musician. but i think they'd be better if they...er..."opened their horizons."
