I use them. My current rig is an Athlon II quad with 8 gig RAM, onboard video and sound. I use my FP10's audio for studio work, and just use onboard audio for movies, etc.
So, no need to spend money on a sound card or video card. Spend that money on more hard drive space!
My motherboard is a Gigabyte GA-MAGPMUD2H (or something like that!). I don't think they make them anymore, but something along those lines works for me. I do everything "in the box" and am heavy on plugins.