What's the model number of the cameras and how did you decide on those cameras?
I've been looking at putting a system together and I know I definitely want to do PoE IP Cameras. Like you, I'm also in IT so I'm comfortable running CAT5/6...as I already have done at my place. I figure I would start small with maybe 4-5 cameras and then grow to maybe 15-16 at the most.
I originally assumed I would do a PC based machine, but I'm starting to think now an NVR might be the way to go because of cost.