Aside from games and a few video editing programs, what are you doing that requires a dedicated video card let alone a bleeding-edge video card?
A Media Center PC based on a Mac.
In light of the previous "want" list, I'll buy the best product that offers this:
Fast Intel Core 2 duo or better, maybe quad-core. Octo seems like overkill.
Upgradeable RAM, at least 4GB max capacity, and as fast a bus speed as possible.
Multiple hard drive capability (I'd love a convertible 1x3.5" or 2x2.5" drive tray in the machine) e-Sata external port would be welcome, too.
optical and copper-based multi-channel digital audio in and out, home-theater grade.
HDCP compatible video hardware, dual DVI (convertible to HDMI) output, fast enough, with dedicated VRAM to render 1080p suitable for TV playback, or BluRay playback. Connect HD monitor and digital audio and go.
IR remote reception, FrontRow integrated.
2xFW800 or better, several USB2 or better ports for peripheral TV tuner, radio antenna, control interfaces, etc, and external drive interfaces.
802.11n, Bluetooth 2.0 or better, gigabit ethernet port.
With some peripheral pieces like DVR-capable HDTV and HD/analog radio tuners, external digital audio processor/5.1 or 7.1 amp unit, and an external TimeMachine-compatible backup drive or TimeCapsule, with wireless bluetooth keyboard, mouse, and bluetooth or IR remote, and a gigabit ethernet download line and FrontRow/AppleTV-like console as default front interface that integrates those features, it could be a full-function Apple HTPC. No second box AppleTV device required. I don't want more boxes, I want "one box to rule them all," and replace most of them.
If I could get that, the audio processor/Amp, and a good LCD 1080p monitor, I could replace my whole analog-grade Home Theater with digital, and be ready for the final Digital TV and continuing HD up-conversion in the industry.
IF that isn't a REALLY good use for a headless, multi-monitor capable Mac Mini, or mid-tower system, I am at a loss. Mac Mini has most of that, except a few crucial points. A Mac Mini, Mac mid-tower, or a third party mid-tower that was configured as such, could do just as much or more than a Mac Mini, iMac, MacBook, and even nearly a base MacBook Pro could do, and successfully underpin the Apple computer hardware lineup under the expensive Mac Pro, and be a multi-monitor alternative to the iMac, rather than a red-headed step-child. (I like red-heads, though so I hope they do well, too.
This 3rd party headless mac could perform well as an HTPC, with it's expandability, although the Mini's optical audio ports, and other things might be better. So still no complete solution.
I want my home theater as simple, slick, and versatile as my iPhone. With Mac OS, and useful well-designed software at it's center.