I'm comfortable with CSS and HTML but I'm not very good working from a blank slate so I tend to grab a plain HTML theme from ThemeForest (http://themeforest.net

I'm comfortable with CSS and HTML but I'm not very good working from a blank slate so I tend to grab a plain HTML theme from ThemeForest (http://themeforest.net http://themeforest.net) and then modify it myself (usually: recoding it to use Blueprint, removing excess elements etc, changing some styles). I find their themes to be generally of good quality and amenable to such modification.