You'll have to upgrade some or all of your other software, too. Best wait and buy a whole new system after we get through the infant mortality phase.
I have been trying for the last two weeks to get a new computer (ours is about to crash). Weekend before last it was hard to get anyone to help at Best Buy (too busy). You could buy a computer and got a coupon for Vista. This past weekend they wouldn't sell any computers because Vista was coming out Tuesday.
I went to Best Buy this morning. There was a crowd waiting at the doors before open. All were there to buy new computers (me included). Got what I wanted and left 3 hours later. Warning: It takes about an hour to boot the computer the first time with Vista. They'll do it in the store for you and it's free check.
I could care less about Vista. I just needed a new computer.