I did a search and I found a couple ancient threads that were similar (Favorite Song & Favorite Singer) but I don't really feel like bumping so let's do this.

I don't really have a singular favorite artist, but these are some of my favorites:
Dashboard Confessional
Say Anything
Coheed and Cambria
The Get Up Kids
Sufjan Stevens

Honorable Mentions:
The All-American Rejects
Arcade Fire