You guys will probably think I'm crazy but I have 102 tabs open in Opera right now.
I also have pidgin running and 3 mrxvt terminals all running `vim` using `screen`, and thunar on XFCE and I have 768 RAM.
Still, Opera is smooth as ever
Of course, I've disabled a lot of the flowery stuff on Opera...I've found that the feature where you display a thumbnail image when you roll over a tab to be the most memory intensive.
If I open Firefox right now with even 10-20 tabs, it's just going to run really slow!