I've been considering puchasing a Synology NAS to serve for multiple purposes. Initially I wanted it to store documents, pictures, and videos but I've also had a need for surveillance as well. I really like the Synology platform but I need it to enable iTunes Home Sharing which it doesn't; it only shares to iTunes and not Apple TV and/or iOS devices. So keeping pictures and videos will not be an advantage.
I really like it's surveillance application, so I am still considering it but I'm also considering purchasing either a Windows PC or an iMAC to serve as my central data repository. Having an additional computer would help us and solve our Home Sharing requirement.
As for features of the software I need the ability to mark areas to monitor motion. The cameras I'm currently using can monitor for motion, but only on the whole video feed. I want to be able to select which sections to watch (for example, I dont' care if someone drives by the place but if they pull in the drive I want to know). It needs to be able to send emails on events. It would also be great if I can somehow program it to ignore animals but I'm sure that would put me in an enterprise level which really exceeds my budget. I don't have much of a budget for this; I want to stay below $1,000 for the computer and software.