Best thing to do it get a smallish system drive for the os and apps, say a 120gb drive or something, then have a drive for storage (possibly 2 500gb drives in a raid 1 mirrored array) (or just have 1 if you have everything backed up on the dv tapes) and then get another drive for rendering, around 250gb should be ok.
2gb RAM should be fine, I'm managing to edit HDV 1080i footage on 2gb ram and a now very old a64 3200+! will hopefully upgrade to a core2duo 6600 at some point this month but this is because I want to play games too. In fact that might be a better idea for this system as well, I don't think you'd see much of an advantage using quad core for simple editing especially as I can edit HDV on a single core although not ideal.
Graphics card doesn't really do much at all so just get whatever's cheapest.
That's all I can say for now, I'm still looking into motherboards.