I like OmniWeb as a web browser. It has a lot of really nice features. Versions 4.2 and earlier can be a little slow, but 4.5 (currently in Beta) uses the new Safari engine and is much quicker, at the expense of a little attractiveness.

I also use Fire now for IM, as I didn't like Proteus's change in licensing. Proteus has a slightly better UI, though. Actually, Adium, I think, has a wonderful UI, but it only does AIM.