Western Digital has a line of AV drives that are specifically designed for DVR use. They’re only slightly more expensive than their standard drives so it might be worth a look.
I had a pair of 2250’s in my HTPC for a short while and they didn’t perform as well as the external V-Box USB tuners I was using just prior to that. I have since switched to four HP USB tuners (rebadged HVR-950Q’s) and they are the best I’ve tried so far.
