Mythbox Hardware
New System
Most posts on here will be about setup for the new system, it should be obvious where they talk about the old system specifically (there’ll only be one post, and it’s gonna be about lirc remote setup and a nova-t PCI card)
Acer Aspire Revo 3600L – nvidia ion and atom 230 (single core) based system, draws something like 25W at full load. 2Gb RAM, 160Gb HDD.
Hauppague Win-TV nova-T USB stick. I’d recommend this, easy to get working (PnP) and passes the full transport stream to mythtv so you can record multiple channels on the same multiplex. There are different versions of this, mine looks like this:

Microsoft MCE Remote, version 1 – If you want to learn about the different versions, see here.
Old System
A HP W6000 workstation Modded slightly, with the fans replaced with silent ones.
Dual 2Ghz Xeons
1Gb 800Mhz ECC RDRAM
250Gb Samsung spinpoint (nice and quiet)
Hauppague WinTV Nova-T PCI Tuner and remote.