One thing I've been working on recently is installing a security system for my home. I'm going as DIY as possible to avoid vendor lock-in, and allow me to use any IP camera that uses PoE, RTSP, and ONVIF. Using FreeNAS for the storage, and a zoneminder FreeNAS jail for the software.
Also got a cool new PoE extender switch that allows me to run one Cat6 STP line over 802.3at and serve 4 PoE cameras over 802.3af. If you have to run cable through an attic, you would love this!
This is what I mean. The last photo is of the side roof cavities that I can easily run a fish tape through. Going in the attic and trying to get a line out to the side cavity is, um, lets just say its a headache.