IM not a fan of upgrades, I prefer fresh install from scratch.
This ^^
Back up all your stuff to an external drive, if you're not confident, get a 14yo to help
Start with a fresh install, and you won't drag all your old problems along.
BTW, if you thought Vista was a PITA, you wait until you're balls deep into Windows 8.
I have about 180 machines, all running Windows 7 Pro.