>My understanding is MS has put a lot of effort into making upgrading less painful. But, if you have a complex environment set up on a laptop - who knows how well it will work? I prefer fresh OS installations.

I had to do a fresh install for Windows 7 as that one was the 64 bit OS and there wasn't any way to upgrade. IAC, it was time to go fresh. So, that was a good occasion to reinstall everything. I just don't want to do that at every OS as this is a full week of investment everytime.