Safari is my favorite browser for many reasons, it’ll also be my browser when I get my iPhone, the only time I have to switch from Safari is to use gmail’s built in IM client (which Safari doesn’t support) and also to get the WYSIWYG toolbar in the wordpress editor. Both of these issues are resolved with Camino, which provides similar usability to safari (great) and similar functionality to Firefox (great).
There’s discussion of which Mac browsers support the Wordpress Editor WYSIWYG editor here.