Fuuckk! I was gonna start a Punk thread, seeing as its pretty much my fav. genre. Serves me right for being lazy.
Anyways, what type of punk are you looking for? If you are wanting to get into Punk you absolutely absolutely absolutely have to get your hands on "Never Mind The Bollocks, Here's the Sex Pistols". I tend to agree with Fat Mike from NOFX when he says that there is no other album that has that much intensity, anger, rawness, just...Fuck! You have to listen to it, freaking legendary.
You also definately have to check out The Clash. London Calling, and pretty much The Singles are an absolute must. IMHO, in order to appreciate the music you gotta check out its beginnings.
Then move onto the hardcore punk stuff from the 80s. I see some good bands, Black Flag, DK, Circle Jerks, Bad Religion, Adolescents, but you HAVE to check out Bad Brains. You will get into a rage listening to them, its overwhelming. And definitely Subhumans, amazing tunes, amazing lyrics.
Social Distortion are one helluva band that you must check out as well.
Then yeah, Rancid are always good, Anti-Flag, Pennywise, The Briggs, etc. Your on the right track.
And for Ska, Op Ivy, Less Than Jake, and some NOFX.
Mssge me if you want some more bands, I know tons. And if you really wanna get into it, watch some documentaries or read some books. Me being absolutely obsessed and part of the punk scene, have learnt a lot from Punks Not Dead, American Hardcore, and books like My So-Called Punk.
I'm happy/surprised there are so many people here that listen to actual punk!