I agree, that NIC would be way better attached to a good sound card since they would be things that aren't replaced often. On board NICs and Sound both suck. I have yet to come across on board audio that is even close to my old Sound Blaster Live! 5.1 (although I replaced it with an old Audigy 2 a year ago 'cause the Live! 5.1 didn't work with Vista. I should see if it works on 7).
I'm going to have to drop my sound card at some point since boards are coming with fewer and fewer PCI slots. If I could get a combo sound card, NIC, and TV Tuner all on an x4 or x8 PCIe card, that would be pretty sweet (should be doable since those are all x1 type cards)