Checking the logs of the HTPC, I found that the Simpsons didn't record because there was no tuner present. Sure enough, in Device Manager, there isn't. Digging around, it seems that the Avermedia tuner card I have disappears in S3 sleep, and then you have to unplug the PC for a few minutes to reset it. Jeez. The new motherboard doesn't support S2, so I've set everything to go to S4 hibernation, and it seems to be working now. It just takes longer to start up, and I'll have to keep an eye on it to make sure it's pulling the guide data down when we're watching TV (as it won't start itself to do this overnight). I'm also going to look for a good deal on a better tuner card, as I now have 2 PCIx1 slots I can use.
We also went out and met Jen for dinner.