I have a few bands that will just always be my favorites, and a few that change all the time. Same with songs...
I'm obsessed with Wilco. Seriously. I ♥ Jeff Tweedy. Actually his birthday was just a few days ago...*rambles*
I adore Rilo Kiley. Blake Sennett and Jenny Lewis are wonderful.
Also Andrew Bird (HERETICS AND FIERY CRASH!)
Right now I also like the Arcade Fire and the Shins.
And my song obsession of the day is Always by Rilo Kiley.