Explosions In The Sky
http://www.imeem.com/birdmad2000/music/PRdC3dO6/explosions_in_the_sky_yasmin_the_light/
Mono
http://www.imeem.com/people/oTuatw/music/7zhNZvgE/mono_halo/
Red Sparowes
http://www.imeem.com/people/oTuatw/music/7zhNZvgE/mono_halo/
Tortoise
http://www.imeem.com/people/Lv2cFy/music/uLw-zhhy/tortoise_jetty/
Kinski
http://www.imeem.com/subpopsxsw/music/E0m4eEJJ/kinski_semaphore/
Russian Circles
http://www.imeem.com/fwooshfx/music/Q6Sq3S_O/russian_circles_carpe/
Rachel's
http://www.imeem.com/people/chO_Hi_/music/k3heSXF6/rachels_rhine_courtesan/
Don Caballero
http://www.imeem.com/doncaballero/music/claF0SHz/don_caballero_palm_trees_in_the_fecking_bahamas/
Stereolab
http://www.imeem.com/todayiwasanevilone/music/JRBD_Moa/stereolab_jenny_ondioline/
I happen to love the post-rock genre. To me it's the most exciting thing coming out in music today, awe-inspiring soundscapes that suck you in. I'll add some clips in a bit but I've got to eat.
The thing about post-rock is it's a loosely defined genre, not many bands happen to sound the same. It's more based on rhythms and chord progressions that are not found in rock tradition (yes, that line was stolen from Wikipedia.) There's tons out there to explore and everything people have named on this page is a good place to start. Let me also throw out Envy as a band to listen to. I think of them more as screamo (and I hate Screamo) but Wiki considers them as post-rock and they are by far the best band I've found in the last year by a mile. Real emo, not the crap that passes for it these days.
http://www.youtube.com/watch?v=hp_4wVg-Ti4
http://www.youtube.com/watch?v=yLyZNEfPqxw&feature=related
http://www.youtube.com/watch?v=-Pd1YSVLfZ4&feature=related
Emily, good call on Slint, the godfather of them all. If you haven't heard their two song e.p with Glenn & Rhoda, give it a listen. IMO it's the best thing they did. The For Carnation was another good Brian McMahan band.