I've scrapped my 5.1 receiver for a 4.0 channel setup. I've substituted an ARC SP-6a (updated) for the front and ordinary stereo use; substitted an Audionics BT-2 for the rear channels, and eliminated subwoofer by using Thiel 3.5's which are flat down to 20HZ (with equalizer). The power amps are Outlaw 200 monoblocks, which have the advantage of being triggered by the audio signal, so the rears shut off when I'm listening to stereo only.
I used to think I couldn't live without matrixed surround sound for my phono, tuner, and tape sources, but I have found returning to a really good tube preamp more satisfying and I no longer miss it at all.
There are may ways to skin the cat with a little imagination.