A clean install is always best as it doesn't import corruption from Vista.
Make your Vista recovery disks if avail, back up your files externally or to a secondary drive, gather your program installers.
Boot the DVD, select Custom install, use Drive Tools to delete all, create new partition(s) as you wish, then format before installing to first partition.
The installer is driver
complete, with newer being quickly delivered by Windows Update. Any missing drivers
or favorite apps can be found on the maker's Support Downloads webpage for your model computer, Adobe (Reader, flash) and Java (runtime, free Ofc suite) sites.
Take your time to install programs to check performance after each. Don't let them Startup with computer (in msconfig>Startup) unless they absolutely need to be running when the computer starts - most don't, only AV and perhaps gadgets or IM.
When you have it setup the way you want and it's running great, save a Windows 7 backup image externally so you never have to reinstall again, just reimage the HD (or replacement) in 15 minutes using DVD or Repair CD.