A lot of Davinci and OMAP chips from TI now feature ISPs. Assuming it's easy to rig this to normal linux software, you could have it react differently based on what it recognises from the video feed (or from still frames).
It would be interesting to have something that could place various "targets" at various "levels". For example, for a stranger, the locks remain shut, and if the user is out, the sensors in the house turn up to 11, and the user gets a phone call letting them know someone's at the house (or a MMS/e-mail might be better, with a photo of who's at the door). Or you could configure it to fire tasers out if you feel like goin' back to jail.
Ideally you'd just have it to recognize when a friendly shows up, so you'd get an alert telling you $friend was at the house.
But the asker has an apartment, so I guess an ISP is a little harder to use, unless he can set up a camera to check outside his door without having it break easily. These sort of things can be networked to a DVR, be it a hardware solution or a mythbox or something.
(I guess all that to show that video cameras are not useless, just not thought out enough)