Mikmo, IMHO all you need is a stereo amp (your budget and speakers will dicatate that), a DAC to pipe your digital signals from CD, DVD, TV, DAB, Pc etc. This hooked up to your amp will save loads of ICs, cheap DACs are available that are stunning sounding. Look at the Beresford/CA DACMagic threads.
Finally kick the 5.1 rig into touch, unless you spend 51% of your time listening to 5.1 i would concentrate on a Stereo system.
The beauty of the amp I linked to earlier is that it has a DAC built into it - a stereo one !!