Earlier quoted context omitted.
W.T.F. I can't go over 6 without feeling messy.
How you feel doesn't really matter when you're doing anything other than idle browsing. This morning I had about 30 tabs open when I came into work, all documentation or reference of some sort that I will use in the next few hours. And thats about the lowest I ever get, if I'm looking up something new to me or complex it will easily shoot over 100.
I recommend a vertical tab addon (I use Tree Style Tabs) else you'll wear out your scroll wheel on the tab bar :)