i like pretty much anything except popular country music and some of the really noisy experimental japanese and goth stuff (i.e. brighter death now).
i guess i'm most into what would be called college rock or "alternative". in any genre i like i definitley have favorites and stuff i won't listen to if i was paid money.
some stuff i do like a lot:
queen
my all time favorite band. not much to be said. if you haven't heard them, you should.
low
my favorite currently active band. from duluth minnesota. they are often catagorized as "slo-core".
nada surf
you might remember them as the band who sang "popular".
i'm the head of my class, i'm popular
i'm a quarterback, i'm popular
...and you'd be right.
you might also remember them as a one-hit wonder.
... and technically, you'd be right, though it would be a grave misfortune to let that keep you from hearing the incredible music they've recorded since then.
elliott smith
one of the greats. you have probably heard his jangly, beatles-y, singer/songwriter type music on the soundtrack to "good will hunting".
the innocence mission
superb, emotional, folksy, pretty music.
the beatles
of course.
radiohead
the beatles of our day.
muse
for those who like radiohead, this band is slightly less experimental, but no less awesome, in sound, musicianship, and songwriting.
sly and the family stone
how could anyone go through life and not like this r&b/rock band? they could be the sole entry in the encyclopedia under "popular music".
sigur ros
hard to quantify. inhumanly beautiful music, just find some, and play it on a good home system with large speakers with a broad, clear frequency range.
failure
happened to come on as i was typing this. i don't often think of them when answering these sorts of questions, but i do really dig them (and anything ken andrews has done since). think of them as a sort of tool or deftones-lite with a poppier, but still heavy, sound.
lush
shoegazer at it's best. i cried the day chris ackland (and subsequently, this band) died.
ben folds (and the ben folds five)
outstanding songwriting, visceral piano playing, extremely real and sometimes gut-wrenching emotional content.
doves
acting as coldplay's darker step-cousin, the doves provide superb brit-rock.
...and you will know us by the trail of dead
they may get the vote for coolest band name ever. they also make uncompromising proggy, noisy hard rock.
snow patrol
a relativley new favorite for me (only a couple years). i was waiting for them to put out something sub-par, but their albums just keep getting better.
the polyphonic spree
joy, personified.
ac/dc
mostly just the bon scott stuff and the first couple albums w/ brian johnson. i kind of hate to put them on a list of my favorites, but every time i listen to their stuff i enjoy the heck out of myself.
bob mould (and husker du / sugar)
bob mould should be treated and respected as the god of music that he is. period.
stevie wonder
see: bob mould (above).
slint
one of the best bands you wouldn't give the time of day to. if it wasn't for them, modern alternative rock would be a very different animal (along with the melvins).
yo la tengo
don't mess with hoboken.
some other notables off the top of my head:
the rolling stones, the who, led zeppelin, the doors, the police, the kinks, the smiths, spiritualized, nina simone, johnny cash, patsy cline, coldplay, eels, berlin, lamb, dj shadow, moby, the stone roses, deftones, tool, godspeed you black emperor!, soundtrack of our lives, echobelly, cranes, rjd2, soundgarden, pearl jam, brendan benson, jimi hendrix, the dandy warhols, beck, duncan sheik, gloriadeluxe, keane, ash, portishead, kings of leon, kool and the gang, son volt, wilco, uncle tupelo, gillian welch, the killers, foo fighters, matthew sweet, liz phair, lycia, labradford, nine inch nails, ministry, fluke, depeche mode, belle and sebastian, bis, jurassic 5, blur, bruce springsteen, squeeze, travis, death cab for cutie, the cult, rush, hooverphonic, james brown, simon and garfunkle, elvis costello, burt bacharach, miles davis, charles mingus, war, fleetwood mac, judas priest, jane's addiction, rage against the machine, remy zero, the melvins, the folk implosion, semisonic, nirvana...