Reinstalling the OS from generic media is my personal preference for any new computer. Get rid of the crap the OEMs bake in.
The only time this didn't work well for me was Vista pre SP1. The OEMs seem to be able to get the machines to run OK, but damn, once you blew their install away and installed from generic media and then installed the OEM's drivers - it was never as good.
But outside of Vista pre SP1 - I've never had an issue doing this.