Not another Mac Mini
I think this may be Apple's version of an HD home media server using Macintosh hardware and software technology. However, unlike Microsoft, they will not try to make a dual-use PC/Media Center. It will ONLY be a media and communication device.
The success of the iPod and iTunes Music store has put Apple back in the game. A new iTunes Music/Video/Movie store will be the Trojan horse to the living room. This is one of the biggest reasons they partnered with Intel (and Intel partnered with them) - the potential for incredible high-volume sales using the lowest-cost hardware available. They have the name-brand recognition and retail presence they need to get this to the masses. Their biggest problem may be competition with cable and satellite set-top boxes and whether or not the cost dictates the need for a service provider business model.
I think this new product will be in a standard DVD player form factor (done right the Apple way) with the following features:
HD DVR (with Apple's version of a TiVo-like service)
iTunes (with new Music/Video/Movie store)
iPod interface (using USB, not a direct dock connector)
CD/DVD play/record
Photos (iPhoto lite)
Communications - video, audio, IM, email (iChat AV, Mail)
Front Row (10-foot user interface)
NO Finder (It's not a computer!)
Hardware:
CD/DVD R/W (SuperDrive)
NTSC/ATSC/QAM tuner
CableCARD 2.0
HDMI
S-video
5.1 digital audio
Ethernet (10/100)
WiFi (AirPort Extreme)
Bluetooth 2.0
USB 2.0 (iPod, camera)
FireWire (iSight, camcorder)
3.5" Hard Drive (lowest cost, highest density)
IR Remote
Do I have a clue? Only Apple knows for sure.