Athlete - Can't even get the "Tourist" CD in the US, but it is very good.
Earlimart - a US band whose most recent CD sounds like a cross between Elliott Smith & Death Cab for Cutie - not wholly original I suppose, but great music.
Sia - Sia Furler. She sang some of the best tunes on Zero 7's CDs, and has a nice CD of her own (another import-only in the US). Very soft rock.
Imogen Heap - Many of you have heard her sing as part of "Frou Frou", whose song "Let Go" was popular on the "Garden State" soundtrack. She has an awesome CD just made, waiting for a label to pick it up.
Rachael Yamagata - A prolific songwriter who tours constantly, she poured out her heart on her first CD last summer. One of the best live singers I've ever heard; her voice can go from Fiona Apple to Janis Joplin in a single verse. How she can belt out music like that night after night is beyond me.