old stuff-
get the Nuggets comp/box
Back From the Grave comps
Sonics
Monks
more recent stuff-
Reigning Sound
Oblivians
Reatards
Hunches
Ponys
Hipshakes
Listen to this guy! Especially something like Nuggets is great way to find great songs for cheap... for the new(er) stuff Reatards might actually be my favorite band...
More awesome stuff:
Jay Reatard and all of his other bands/projects too
TEENGENERATE (already mentioned, it so good)
and other RIP OFF RECORDS stuff (Loli & The Chones, Registrators, The Rip Offs, Supercharger, The Zodiac Killers)
The Devil Dogs is an essential 90's Garage revival-band
and New Bomb Turks too.
Black Lips does the hippygaragething and is awesome
Roky Erickson and his bands going all the from the 60's to the 21st century (check out The Psychedelic Sounds Of The 13th Floor Elevators by 13th Floor Elevators)
Boston Chinks (great band)
Carbonas (same)
Mark Sultan (also known as BBQ) and King Khan too (check out The King Khan And BBQ Show for their collaboration)
M.O.T.O. (great garage rock'n'roll)
The Mummies (legendary liveband)
The Wongs (holy shit!)
Well, I quess I forgot like 1000 bands, but whatever. Some of those should get you started both on the 60's Garage AND the 90's revival AND the recent garagepunk/rock stuff. Some genre lines could have been crossed, but who the heck cares about those anyway.