Blimey - I'd never had guessed that Opera is so popular.
It's IE7 here, though public-access labs seem to have Firefox 3 installed too.
Staff have just moved to IE7 this week, student machines move to it once some problems resolved. Several staff use Firefox though, and web team develop for that generally.
IE6 right now, hopefully IE7 by the end of the summer. Student PCs are currently on IE7, hopefully IE8 by end of summer. My preferred browser is Opera, which I use at home and used for a long time at work (I have more admin rights on my PC than most so could install it), but recently my PC had to be reinstalled so since then I've used Portable Firefox 3 for things IE6 can't handle (e.g. Yahoo Pipes).
Btw why on earth has someone hijacked the poll to show a zillion Opera users? Bizarre!
We have IE6 as our standard browser, but we also have the alternative of Firefox - version 1! If we want a different browser/version we can put in a request but have to go through the laborious process of form filling and getting line manager's signature etc. I tend to use Portable Firefox 3.
We're still IE6 for another month and then we are moving to IE8. Also since we are a Mac and PC organisation many people will use Safari as its the default for a Mac. Firefox 3 is also available to install if people want to and many people do.
Sad, so sad, that everyone's saddled with such unusable insecure junk
We had hope to moe to IE8 as the default this summer, but since we're changing our single sign on authentication mechanism, it was felt wise not to change both things at once.
We don't prevent anyone installing and using any other browser, but only IE 7 is "supported" and the other browsers are not 'managed' in any way. Most of out intranet and other systems only work fully with IE7 and later as so much is based on MS architechture and technology (OWA and sharepoint both lose significant functionality on anything else)
IE7's the default, but Firefox 3 also available. No others, though. (At least, not on the PCs; less sure about the Macs)