I've plumbed for a mixture of streaming and static (offsite) images. I spent £90 on three cheap IP outdoor wifi cameras, positioning them over the exterior doors and front garden. Once configured, I didn't use the built in web server at all, instead using a program called Motion on my media PC/home server to plug into the feed generated by the cameras and detect any changes in the image.
Each of these snapshots are then saved to an images directory and uploaded via SSH to a remote web server where a simple web page with a minishowcase JavaScript gallery picks up everything automatically and displays the historic stills in order. A cron job deletes everything older than 5 days old to preserve disk space.
There's also a live feed that runs from Apache on the home server, which picks up the snapshot.cgi of each camera and refreshes the images using JavaScript within the page. That way the actual web server of the camera is not exposed to the outside world.
Took a bit of fiddling about configuring the internal network, subdomains and url forwarding in Apache but it works pretty well. The idea is that you can see on the live feed if there is a problem, then trawl through the stills for the evidence. Unfortunately, the cheap cameras let the whole thing down a bit, my grass looks more purple than usual and I'm sure my bald spot looks bigger...