On a side note, if you are thinking of getting a new PC, I would recommend you get it now before you are forced to take an early version of Vista. You want to wait as long as possible until the majority of the security issues are solved.Anyway, back to Firefox... I have installed version 2 and have used it both at work and home without any problems. I did have to update an extension and removed the anti-phishing, as it is now built into Firefox, but other than that all is good.
I do not see a big difference from 1.5 to 2.0. My hope is that it does a better job managing memory -- occasionally in the past, if you surfed a lot and/or had the browser open for a long time, it would begin to slow down as it consumed more and more memory for caching.
In the Options, I set the Feeds to Thunderbird but have not had a chance to try it. This looks like a new and easier way to subscribe to new RSS feeds.
Firefox's tabbed browsing was updated as well. Now if the tabs exceed the window width, you will get left and right arrows to scroll through the tabs. You can also select a new active tab from a drop-down arrow on the right. Finally, the close tab button is on the right-side of the active tab instead of the right side of the browser window.
One other feature note: Firefox now has built in spell checking. This is a great feature if you have a blog or use online email.
So, if you have not downloaded Firefox 2 -- the time is now.