Completely with you there. Safari was my primary browser (and has been for about a year) until a friend mentioned that Firefox 3.6b5 had some major retooling with respect to perceived performance (esp. in the address bar and page compositing engine).

I'm really enjoying it so far, but had to switch to the GrApple Yummy theme at the above link. The base Firelight treatment feels so bulbous with a lot of wasted vertical space and unnecessary large rounded elements.

I love this UI concept series, though - the proposed Windows design is gorgeous. I'm jealous of how beautiful Chrome and the new Firefox 4 concepts look with Aero compared to their bulgy gray counterparts on OS X.

Never thought I'd say that :-/