I have built AMD AM2+ HTPCs on IGP and users ditch sound card for USB DAC for audio set up with great results. The introduction of a discrete GPU causes more heat, power and noise to generate and if you go to AVS subforums dedicated to HTPC DIY people are using IGP+GF8200 just fine for Blueray Lastly a recent project log i did (we have a mATX 790GX here hehe) The Making Of: Fatcat HTPC!!
With the event of the new and improved Cool n Quiet 3 though if i want to go with a discrete:
P2 X4/X3 Energy Efficient chip version
GF98xx or GTX 2XX
Cool n Quiet 3 + possible undervolting + Geforce Boost + Hybrid Power