Hmm, did some more testing out of my own. This is what I think so far:
Internet Explorer 9: Huge, huge improvement over previous Internet Explorer versions. I'd say its become a modern browser now, and a viable choice for a web browser.
Firefox Beta 11: Nice new interface, the most customisable of all the web browsers as normal. I'd say Internet Explorer 9 is faster than Firefox Beta 11 (at least for me), though the customisability of Firefox is worth using it alone.
Latest Chromium/Chrome Canary Builds: Holy cow, they are fast. Fastest thing I've used so far. Scratch that. I should say