I'm sure this is linked elsewhere, but if anyoine is interested, there's a
review of the Shuttle SS50 on The Tech Report. In addition to 2PCI, 4 USB, 10/100 ethernet and 3 IEE1394 ports, it has an svideo out and a 6-pin mini DIN for 6-channel surround sound.
The interesting part is that they didn't kludge the built-in sound, ethernet, etc. capabilities of the SIS 961 South bridge, but opted to add a separate C-Media 8738 audio chip for the six channel sound, a Realtek ethernet chip, and a SiS 301 for the Tv encoding for the Svideo. All in all, it's got a lot of speclty chips where most small form factors try to (over?) leverage a few multipurpose chips.
Is the on-board SiS 301 adequate replacement for an AGP slot? Maybe not. But the PCI slots have enough room for a PCI Voodoo 5 card or similar large PCI video card, per the review, and I don't think an HTPC really maxes out a PCI slot the way a 3-D game might.
The Tech Report also says it's whisper quiet.