The 5800 (or similar receiver) is a perfectly legitimate option; however, it depends on what you're after. If you want to optimize 2 channel listening, there's no way a receiver will do that. I don't have to imagine it, I tried it, for some time, in the same room. Indeed, a receiver probably won't optimize the home theater listening either. Another, probably better quality option is to have a great pre-pro as suggested by some of the posters above with great outboard power amps, and drive your 2 channel using the digital bypass available on most pre-pros. This can yield excellent 2 channel performance, but not as good as can be gotten with a great 2 channel preamp.
That's not to say that the 2 channel (and HT) performance can't be excellent. My experience (and preference) is that separates sound better $ for $.
I also don't think it's necessarily true that a 5800 is any less "clugey" than a separates approach. Indeed an argument can be made it's more of a cluge. At the end of the day the only thing you save is a handful of interconnects. I have a Sony ES receiver in my living room system, and the cabling is a mess.