Along the same lines as the in-car system, I'd like a fully automated home. All appliances tied in: electric, heat, light. With a voice-recognition and audio response system, and fully scriptable interface. Also, a nice, truly secure (HA!) remote interface would be great.

Me: Home?
Computer: Yes?
Me: Living room lights, 50%
Computer: Certainly

And again, feature-creep being what it is, I'd look forward to the fun I could have. :)