- Opera has an email client. But it's kind of a joke. I use Thunderbird for my mail.
- Opera has a chat client. So what? There are plenty of chat clients.
- Opera has mouse gestures. I don't care; others do I guess.
- Opera treats tabbed pages as 'real' windows. I just find this handling annoying and I don't derive any real benefit from it. I like Firefox tabs just fine.
But it's the little things that keep me on Firefox. Flashblock, Adblock, and Noscript make browsing a pleasure. The Google toolbar puts the words I searched for on the toolbar so I can just click on them to find them in the current page. The Firefox proxy settings page lets me set a subnet that won't use the proxy. I couldn't figure out how to do that in Opera, and the help didn't.
So I'll stick with Firefox. Trying beta 2 right now.