With the release of Internet Explorer 7, I have been hearing that the "browser wars" are back. (Hopefully, the return of the browser wars will turn out better product than the return of Star Wars did.)
I haven't upgraded to Internet Explorer 7 yet, so I'm not sure if it is much improved. IE 6 is perfunctory but the only enhancements in ages came from add-on Yahoo Toolbar and Google Toolbar, which offered easy search, customizable shortcuts to features and services, and the much-needed pop-up blocker.
I've been using Firefox for awhile now and recently upgraded to Version 2. Didn't notice much improvement. Here's an intro to the various changes.
I love the idea of live bookmarks, but not using them much yet. I prefer getting my feeds via My Yahoo.
Firefox Version 2 added integrated search that allows one to search directly to Wikipedia, IMDB, Amazon.com (wish they had .ca) plus the more popular search engines.
Firefox 2.0 greatest claim to fame may be its phishing protection (for those who don't know a phishing scam is where someone creates a fake, copycat website of say a bank or e-Bay and then tries to lure people to enter their financial info, credit cards, passwords, SINs). Here is an interesting article about Firefox's superior phishing protection by InternetNews.com called Our Phishing Filter is Better Than Yours!.
I have never tried Opera and intend to one day. I have used Safari but that experience was marred by the general goofiness of using a Mac.
I should give IE7 a try before passing final judgment, but so far I'm even more loyal to Firefox.