This sounds very tame now after what happened with the site over the past two days but..... having messed around with all the available browsers I find Opera 10 (for me at any rate) to be the best option. It's faster than Firefox, even after upgrading, and if you can live without some of the extension capabilities I recommend giving it a try. Installed the x64 flash as per these instructions too and YouTube worked first time.
I've always liked the mail integration in Opera and the Linux version works just as well. I guess the overall package is similar to the new Seamonkey suite but it's much better put together and I just couldn't get flash to work in Seamonkey (V2.0) no matter what method I tried.
https://help.ubuntu.com/community/OperaBrowser