Win7 hasn't needed much tweaking here. It did a lot better, before I got stuck unto it, than Vista on a brand new laptop bought by a friend of mine.
That said, I agree with the "Not Windows 7" for your main machine, unless you're into geekery. In part, at least, because it will stop working when the Beta test is over, and you'll need a place to go.
This machine dual-boots to XP Pro and Win 7. Win 7 is faster (by a long way), running all the same software and utilities that I have on the XP installation. Only ZoneAlarm, iTunes and Jepp Datacard Update don't work on Win7. The lack of SCSI drivers for my old card was a minor niggle.