I've been struggling with this issue in a few locations for the past 2 years. I've tried a cheapo 4 camera setup from ebay but the one time that they were needed the intruder unplugged the router rendering the system useless... I'm upgrading that location with cameras that have local storage. I tried Ispy but the yearly subscription is annoying and if you have multiple instances it's tough to keep track (they don't contact you when your subscription is about to end).

As a plus to the recent boom in NAS sales, the major manufacturers have started really beefing up their software so the two bigdogs in the market (QNap and Synology) offer camera software built into their NAS boxes. I have been able to try out the Synology setup but I've heard that the QNap setup works just as well. It's pretty straight forward and I don't think many robbers would think to grab your storage device while running out the door. They both come with limited licenses for channels (read: active cameras) so you have to purchase a license beyond the default per camera you want to use, the synology licensees are a one time cost so it comes with 2 license but I have 3 cameras so I had to purchase 1 license($45) for all 3 cameras to work.