Just to let you know, I'm not convinced on that motherboards ability to output 1080p. The UK abit website says that it will do "up to 1080i".
A point to note as well is that HDMI is _very_ similar to DVI, so much so that you can get simple converters from one to the other.
Another point is that the HVR-1300 only has a single Digital tuner, so if you want to record TV then you either:
a) Watch channel 1-5 live + record from digital
or
b) Watch digital channel live + record from channels 1-5
My final point is that there is software such as Freevo & mythtv that allow you to create a PVR/Media box without having to buy a copy of windows. It may be a bit more involved (although distributions such as knoppmyth can make it easier), but it's free and much more satisfying
Also, if you're going to have this by your TV, it's worth considering the components on the basis of noise. The stock cooler on your core2duo and the HD will produce noise, and you may want to consider alternatives.
(I'm currently putting together a mythtv box with an Antec Fusion, using an old Athlon64 4000+, 1Gb ram and a passive 7300GT)