My basic rundown goes something like this.
As a web developer, I try out and test a fair number of browsers. I use Opera for my daily browsing because of one killer feature for me: the ability to move bookmarks from a search. I have over 4500 bookmarks, and so being able to sort and organize bookmarks is crucial. I mainly use Firefox for development, because nothing's better than Firebug.
Amaya: Worthles, only good for standards testing.
Avant: Basically just an IE extension. Waste of time
Firefox: Memory heavy, and can be slow when page loading. Balanced by community support and popular conformity.
iCab: Tiny, and with a few good fetures, but not very widely suported, and kinda silly.
IE: points for integrtion, but slow, and still not quite standard. haven;t tried IE 8 though
Opera: Too many features, but that means there's something for everyone. The program is huge, but doesn't leak to much memory, and new beta has very fast page loading. Some issues with JS though.
Radon: Not a bad microbrowser, but not too much to write home about.
Safari (Win): Does not play nicely with Windows. ood for development, but that's about it.
Safari (Mac): The IE of Mac OS. Moderately fast, integrated, but has JS issues and some unsupported features. Same for pretty much all the WebKit browsers
Ayway, that's what I could think of off the top of my head.