Well... any pc with: - AMD/Intel 800mhz cpu - 256MB RAM - DX7 3D GFX card wth tv out recomended I think this covers the basics. If you want to watch HDTV just double the cpu power, ram, etc. Better yet visit technisat's site. Skystar2 don't like nforce4 chipsets.
As for programs i'd say, go for ProgDVB or MyTheatre plus a softcam emu like S2emu and a working key file, plus a new transponder and channel list. Not much can go wrong with these choices.
hmmmm not sure about the 800Mhz from my experience. Yes, i agree, fine for most things but if you want to watch TPS (footie) then you might struggle (as I did). You can see in DVB dream how much CPU usage there is on each channel, TPS foot / Star is consistently near or up to 100%. I had a 750Mhz PC at first and have upgraded the CPU to 1Ghz. Still a bit 'pixely' at times, slight improvement when i close everything i can down. I would plan to go for at least 2Gb when I next change.