I use Firefox, plain and simple. I tried Opera, and it set itself as default for a bunch of stuff, so out the window it went.
I have Firefox completely customized to just the way I like it. My buttons, user bars, sidebar, right click, everything. I'm sure there are similar things in opera, but I have what I want.
Here's what mine looks like with the sidebar open showing my extensions:
http://img259.imageshack.us/img259/4411/ffscreenkq3.png
Oops. I forgot the IMG code was turned off in this forum. Click the link, then.