I’d go for html framework, they’re far better.
I like whiteboard: http://plainbeta.com/2008/05/20/whiteboard-a-free-wordpress-theme-framework/
I’ve never used a framework for WP or CSS , just because they normally always don’t fit the bill and you end up with all this extra stuff you don’t need.
I believe if you have a good grasp on what you are working with starting from scratch is just as fast as using a WP or CSS framework. But that’s just my opinion, to each his own.
I think using a WordPress framework is the best way to learn how to use it. Trying to figure out what everything does in a normal theme is near impossible for a beginner, but since the frameworks are cut to the bare-basics you have something to learn up from.
I used Starkers by Elliot Jay Stocks when starting out, and am really thankful for it. I’ve now made my sort-of own framework which I build off-of now, and will probably release it when I have time to clean it up a bit.