I use Opera exclusively, especially now it's FREE!! And IE when I come across pages opera can't handle (about 2% of the time).
I love the mouse gestures, now I know them, I can't use another browser.
The way you can magnify is cool too. The tabs, keybord shortcuts, 2 to go to the next tab, 1 to go to the previous, down left to close, down up to open in new window, great stuff.
Opera does crash on me know and again, and it sometimes takes aaaaaaaages to load, but I'll blame the hardware.
It's small, it very quick, and about a fifth the size of IE. And it works off one file, opera.exe!
I just wish quicktime and real would work properly with it!