For SE's sake, I'll put some descriptors for the bands I listed. Just as a reference, I am a HUGE fan of Jimmy Eat World.
Making April--piano rock. Alternative and a bit emo. Some of their songs are almost orchestral (meaning the instruments that they use, it's almost a full orchestra. It's strange...). Some of their songs are more emo than others, especially the ones on their first album. Their newest album (which they view as their debut album) is a bit more mainstream alt rock. They're fantastic lyricists. They use words you don't generally hear in songs, like emphatic, incessant, haunting, etc, but it doesn't feel out of place. Good stuff.
Guster--alternative rock. Some strings. Bongos instead of drums (mostly). I don't really know how to describe these guys other than that.
Between the Trees--indie rock. Keyboard/piano.
Rookie of the Year--indie rock. Sort of emo and acoustic.
We Shot the Moon--indie piano rock.
Straylight Run--indie rock. One girl (she recently left) and three guys.
Secondhand Serenade--piano rock. Alternative and acoustic. A lot like Dashboard Confessional, only John Vesely (lead singer of SS) doesn't get quite as emo as Chris Carrabba tends to get.
Foreverinmotion--one-man show. He describes his sound as being a mixture of folk, rock, and ambient. He did a cover of Jimmy's "For Me This is Heaven" which is absolutely phenomenal. So much better than the original, I think.
Pete Yorn--alt rock. He has a bit of techno feel. A bit...He generally plays all the instruments for his songs (or he did when he first started out), from the guitar, to the keyboard, to the drums, to the harmonica, plus more. Insanely talented.
Nickel Creek--Progressive bluegrass. One girl, two guys.