I admit to being a MCE fanboy, but watch for a few things such as:
I get random video lock-ups, system freezes and reboots within 2 weeks whenever I upgrade my nvidia drivers with the MCE certified ones. This has been going on since my first MCE 2004 system with a 5200 straight through my current MCE2005 system with a 7800 (non SLI). The problems go away when I install the regular XP drivers instead. (Why do I keep trying the MCE drivers? I don't know, I guess I'm a masochist. 8O )
In Oblivion, I got my character stuck in a corner. Even reloading, he would still be unable to move out of it. I tried for help on a gaming forum and everyone told me to bring up the console and type such & such commands. The console wouldn't come up no matter how many times I pressed the "~" or looked at my oblivion.ini file. I found the problem, you have to unplug the IR receiver from the usb port. Soon as I did that, the console came up right away. (Too late, of course. I had already loaded the saved game before that - lost about 3.5 hrs - taught me to save more often and not rely on autsaves :x )
I'm not sure why the IR receiver being plugged in caused the console not to work, nor am I sure if this affects other games. I found this solution mentioned on just one site out of the scores of Oblivion sites I checked at the time (hopefully it's better documented out there now).
I haven't heard of this problem in any other game, but if you do run into any keyboard response problems - I'd try unplugging the IR receiver.