Mine says 1.5.
A techie built me a new computer a couple weeks ago and installed it. I don't know much about what the differences are.

Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8) Gecko/20051111 Firefox/1.5

I haven't really checked out any new features (if there is any) but I found something I don't like. When you try to clear the history & cache and all that stuff, that CLEAR ALL button no longer exsists. You have to go under each of the 6 tabs and clear them individually. Unless I'm missing something, this seams like a step backwards in the user friendly department.