Opera definitively ! . - IE ( ) only if I do Windows update online and not, as often I do, offline. If Konqueror ran on Windows, I would use it also.
I've been a user of Opera for as long as I can remember, right back to when it cost money to buy the full version! Absolutely love it. I use the Proxomitron local proxy for an extra layer of protection and for speed I turn off memory and disk caching. I usually have K-meleon open on Windows as well, with no local proxy, mainly for websites that lose some functionality when using Opera through Proxomitron. Another excellent Windows browser. On Debian/GNU Linux it's a mix of Opera, eLinks, and Iceweaver. IE8 is a vast improvement on IE7 but I use it only in exceptional circumstances, when, for example, it is required. Thankfully this is less and less the case nowadays. I've never liked Firefox on Windows. Slow and clumsy, and I've never liked the idea of having anybody and everybody able to contribute so many plugins to it.
Opera most of all FireFox Konqueror Iceweasel still have to try K-Meleon Never use IE, you used to need it at certain stubborn sites, not any more...Good! Plus, I like downloading and installing.
Just 1 - IE7 -- very fast on my vista laptop -- no problems. On my other XP laptop I use Opera -- much faster than IE7.
Have you tried IE8? Try the x64 version if you are on x64 OS. Although not as slick as Opera, IE has come a long way.
Opera 10 alpha & Firefox 3b1 here. I tend to prefer opera, but can't ditch firefox :] I also like kmeleon, if only they would keep up with the latest gecko engine.
Been using IE forever, but just installed Chrome-beta 2.0.177.1 and I'm sure liking its speed. Chrome takes some getting used-to, but for now it's my default.
IE7 only. I used to use Netscape. Then I tried a couple others. IE works best for me. Soon I'll make the move to IE8... but I'll image the HD beforehand in case I want to switch back quick!