I used to use Opera a lot in the past, and honestly the stock browser is better than anything I've seen from Opera to date. I use Skyfire on occasion, it has a built in flash player as well as your traffic is routed through their servers. It makes for a little more load time, but it helps avoid blacklisted sites.
I use and like the Xscope browser. I'm not too keen on whether it's using Flash (I should be, but I don't pay much attention unless something isn't working), but "it's never met a website of mine it didn't like". And it goes back instantly to the previous website. It's not free, but I found it worth the purchase price.
I'm watching the Firefox beta releases as they come along. It looks and and has some really cool sync features between your mobile phone and home computer. Once it's finished, it should be among the best, no doubt.
Am I the only one that thinks it's odd that Google hasn't made a Chrome mobile browser?
Having said all of this, I don't find anything wrong with the stock browser.
I tried Skyfire, Opera, and Dolphin. I have Firefox on my Computer and tried the mobile version. Truthfully, I always wind up with the stock browser. Can't put my finger on why I like it better than the others, except Firefox, which seemed much slower. Don't care for the interface of Opera. My vote, the stock browser.
3 days ago I installed the Dolphin HD Browser .. I like the Bookmark management ability of it compared to the stock browser. It does seem a bit faster to me. I also like the "gesture" capability in it.