What setings are you talking about?
Everything is conviniently located in nForce control panel: the EQ, the speaker selection, levels for every channel, EVEN the subwoofer crossover! Most probably you have the MCP bridge with just a realtek CODEC. ALSO! Do you have Asus' drivers installed, or nVidia's reference drivers (from nVidia website)? Sometimes with Asus's drivers the nForce control panel simply doesnt install. If so, download the nVidia's drivers, install them, and then the nForce icon will appear on your system bar (if you have MCP-T south bridge) - simply tweak everything as you please.
As for selection between nForce APU and Phillips - i say APU. Im a sound enthusiast. Before, i had an M-Audio scard (250 USD) for music listening purposes only. It had extensive settings too - unnecessary. Also i wanted to check how much worse the s. quality is going to be on APU (16 bit) as opposed to M-Audio's 24 bit. Hooked it up to a Marantz spectrum analyzer, and i was shocked. The deterioration was only 14%!!! (Basically, it means you cant hear the difference). So i'm more than happy with the (30 USD extra for mobo) APU than my 250 doll. M-Audio.