Upside: The AVR-5805 is the world's first receiver with 10 built-in 170-watt amplifiers, which can provide up to 22 channels of sound. In other words, it can power two separate 5.1-channel home-theater systems or, by connecting to external amplifiers, two separate 7.1-channel systems. Aside from HDMI switching (three inputs, plus a DVI input), four-zone capability, and an Ethernet connection for future upgrades, the monster has a specialized room-tuning feature that supposedly corrects for eight different "sweet spots." Mortal room-tuning features make do with one.
Downside: It's huge and expensive. This thing will cost more to ship than most receivers cost to buy. Aside from those obvious issues, most home-theater aficionados in this rarefied price bracket prefer to invest in separates, that is, a dedicated preamp/processor plus a multichannel amplifier or even a separate amp for each channel.
Outlook: Downsides considered, the AVR-5805 is pointed toward a tiny segment of the market. This is a technology statement more than a consumer product, so don't hold your breath for a full CNET review. We'll leave that to our friends at Robb Report Home Entertainment. Those of us without such deep pockets will have to settle for Denon's expanded lineup of less audacious--but still feature-packed--A/V receivers.