Looking for a top notch TV/vid card

Hey... I just recently tried the Viewsonic VP50HDTV video box, and although I'm impressed with its picture quality, it doesn't support passthrough for surround, only direct output. I've got a nice THX compatable Altec Lancing sound system hooked up to the comp, and I'd like to avoid dropping then $$ for a little 3 piece system just to hook up to the TV box. So instead I'm looking for a TV/vid card that will allow me to watch cable TV and be able to play PS2 or Xbox using an RCA or S-Video connector, both with at least as good (hopefully better) clarity than I'd see on a regular TV. Full screen is nice, picture in picture is nice but not neccessary. Any ideas of something that would fit the above? Thanks.