Emeralds are a fucking incredible... uh... ambient band? Noise band? Electronic band? With a lot of shit going on in their sound. One of my favorite albums from last year....
[ame]http://www.youtube.com/watch?v=zHfFZYK81lA&feature=related[/ame]
Fleet Foxes = folk rock a la CSN, sorta, with a shit-ton of harmonies, but a bit darker at times. Doomcifer hates them.
[ame]http://www.youtube.com/watch?v=7m8CkxXhPtw&feature=related[/ame]
Liars are one of the best and most bizarre bands around today. Some heavy, real, dark shit. It's hard to describe their sound, because it shifts from album to album. This is the opening track from my #4 album of the last decade--Drum's Not Dead.
Wavves are a kickass stoner punk band that I doubt many people here would appreciate.
As far as AC goes, it's tough to say. They're one of those bands that takes a while to sink in. I loved them when I first heard them 6 years ago (there are probably some RC posts), then HATED them for the next 4 years after that (the hipster factor). The rest of their albums are vastly different. If I were you'd I'd check out their (almost album length) EP from 09, Fall Be Kind, or Merriweather Post Pavilion from the same year (their "pop" album). If you want to go in the weird direction, go with older albums like Here Comes The Indian or Hollinndagain. Also, Noah Lennox (aka Panda Bear) released maybe the best album in the entire AC canon, Person Pitch, probably one the WEIRDEST things ever recorded. Check that out, for sure.