A list of good WordPress themes both premium and free:
Great minimalistic, typographical themes.
http://www.upstartblogger.com/
Great collection of magazine style themes with great style, clean layouts, good typography.
Great company, good support, good, solid and customizable themes. I use these themes regularly
Elegant Themes is a nice collection, good graphics, but they are kinda bulky. I use them on occasion when I want to spend less time customizing and more time writing.
Good themes and support though I think they are a bit overpriced. They are currently (at the time of this writing) offering a two for one sale. Not a bad deal actually
Great looking tyopgraphically strong theme with good customizability.