I just recently(11-08) started contributing to this Wiki, after being a long time reader. For one, it helps me document my own hacks, especially if I need to recreate them, as well as help others.
I run two MythTV independent backends, one permanent, one mobile.
Athlon X2 5600+ 6GB RAM 1.6TB of Video Storage Fedora 9(x86_64) 1 PVR-250(mostly used for analog conversion and backup for the Firewire connection for channels not receivable via that) 1 Air2PC card(bought on Ebay) for OTA HD broadcast 1 HDHomeRun - Digital QAM 1 Cable Box attached via Firewire
This system is headless, and feeds frontends contructed from its spare parts after its been upgraded, which it has multiple times. Also doubles as a file server.
Athlon BE-2400 45W 1GB RAM Fedora 9(x86_64) - planning to switch this to Mythbuntu, as a way of testing alternate distributions 1 PVR-150 1 PCHDTV-5000
This system is mobile. It has a backend configuration. During the summer, I run it at the home of my relations, as they still have analog cable feed, and I do not. During the winter, when they shutter the place and head to Florida, it returns and acts as an extra frontend for guests and a testbed for experimentation.