So, I'm settling around something like, maybe the Yamaha RX-A820, which has everything I want, but much, much more. Which is, itself, irritating.
And, I want to investigate (at least a bit seriously) the possibility of just buying a multichannel amp and a decent (but not obscene) multichannel dac or sound card. So, I'm very price conscious, but no eBay or Craig's list. I want something with a warranty (but it can be a discontinued model). And, as mentioned above, I don't have any good, local showrooms.
So, with that said... I don't know much about where to start (other than looking at pro gear). Suggestions?
Depending on how "decent" you mean on the DAC/soundcard front, you can find reasonably high quality 8 channel soundcards for about $80 (the Asus DX), and nicer eight-channel soundcards for $150-200 (the higher end Creative cards and the Asus ST/H6 combo). I can personally vouch for both the Asus cards mentioned above, they're relatively nice, and relatively quiet (provided you use the third party drivers). I ultimately needed something lower noise due to some unusually sensitive speakers I was running, but I still use my Asus ST as a source for some other speakers. When you start talking about outboard DACs with eight or more channels, it's hard to find reasonably nice ones below $300 or $400.
You can find pro audio amps with six or more outputs, but they'll tend to be about as (or more) expensive than the receivers you're considering. Also, some otherwise desirable Pro audio amps often have odd numbers of channels that don't really consider home theater users (4, 10, or 12): pro audio 4-channel amps seem especially popular, and some are a good value, like the ART SLA-4, but that leaves open the "what about the other two channels?" question.
Which brings me to one of the joys of having a multi-channel DAC or soundcard: you can mix and match power amps depending on what you need, and you can build the system on a modular basis and replace or add parts as needed. You needn't buy an 8 channel amp, you can buy as many channels as you need or mix and match different amps depending on the power needs of your speakers (large wattage amp for the sub, smaller wattage amps for the surrounds, etc.). If you wanted to upgrade to 7.1 later, you could just get another two channels of amplification, etc. You won't necessarily save money, but it gives you more options if components fail or you want to upgrade later.
To that end, if you're looking for cheap power amp options, I can honestly say that some kind of Class D amp (sometimes called T-amps, or class T as well) is something to think about. They're small, cheap, and use very little power (and can sound surprisingly good). I recently recommended a small 20-watt two-channel Lepai model for Matt's bathroom project (although he hasn't reported back on the amp yet):
http://yabb.jriver.com/interact/index.php?topic=83183.msg567831#msg567831It retails for between $20-25 at Parts Express or Amazon, is about the size of a mass market paperback, and sounds better than some $200 amps I've heard. You could stack three of them and have six channels for $70 or so after shipping (and that stack would take up much less space than your current receiver). I wouldn't necessarily recommend that specific amp for your setup (you may want more power, and it sounds like you're not looking for the setup to be *that* cheap), but you get the idea.
Parts express has a variety of Class D amps, and some folks on here enjoy the Dayton brand amps quite a lot: http://www.parts-express.com/cat/amplifiers/106
In my experience, they tend to be nicer than the Lepai, but commensurately more expensive (but still in the $20 to $50 per channel of amplification range). The nice thing is that PE has a killer return policy, so you could even demo one of whatever you're considering before buying all your channels, and send it back if it's unsuitable.
I'm assuming here that you don't want to spend more than about $300 or $400 on the "amp" portion of the entertainment, and you're not interested in DIY at all. Obviously there are really good five or six channel power amps if you're willing to go up in the $800 or $900's (Emotiva's five-channel comes highly recommended, for example), and I can definitely recommend some DIY power amp options if you're looking for a project :-)