Sean,
I think rjgvt's method is going to be the most cost effective and best choice in the long term. I have a cheap pan/tilt camera with a few IR "bulbs" circling the lens. Some of those IR bulbs have quit working, so the night vision has diminished as more and more bulbs quit working. If you get a camera with built-in IR, you'll eventually have to replace the camera or take it apart to replace the IR board. It's much easier to replace a flood light or 2 when they burn out. Plus, you get color images (with realistic color) and more detail.
If the burglars are still alive, they're lucky...they probably wouldn't be if they got caught down here in Texas. We shoot first and ask questions later. lol
rjgvt,
Great tip on the siren. If I didn't live in a neighborhood with a bunch of stray cats and other random nocturnal wildlife, I'd definitely wire a siren up.