Turn off UAC (it's the annoying thing that nags you about..."Do you want to do whatever your about to do?"...yes...."Are you really really sure you want to do what you're about to do?....)
Change power profile to high performance (turn off power saving stuff, both in Win7 and in bios....bios speed stepping will "step" on you. Common cause of clicks, pops, dropouts etc...).
Be sure you run an ASIO driver for whatever audio interface you get.
Many DAW's suggest you set up Windows to prioritize background processes.
If your DAW is stable, turn off Windows auto updates. many people (my self included ) have had strange problems caused by this. If your system is running stable, and you get some windows update, following which, you start having problems, there is a "Restore" function in windows that will allow you to move the machine back to a previous point (just pick a date from a list and it'll back out whatever updates were done since). I've used this and it works fine.
Most of the early problems with Win7 were related to graphics cards drivers (Win7 implements a completely new graphics interface...early drivers were sometimes dodgey. At this point, most are completely stable so you should have no problems.
Do run x64.
I've been very happy with it and it installed pretty quick and easy.