I spent the last summer working at Best Buy in the computer department. Two of my coworkers(they loved to drag us in for Sunday morning meetings around 7:30
) were beta-testing Vista and they both had the same opinion: it sucks.
I'm sticking with XP. I'll update the RAM, and the hard-drive as necessary, but it'll be at least 6 months, until MS works out the bugs, before I invest in a new computer...