If you are a technically inclined type, here's what I would recommend:
GE Networx/Caddx or a GE Simon system are very easy to install and program. I prefer the Networx/Caddx systems myself. They can be hybrid (wireless and wired) or one or the other, just depends on how you want to set them up. Obviously, wireless is much easier to install.
If you go that route, be sure to purchase the NX-148E or NX-148E RF keypads to go with it, as those are by far the best keypads for this system. The RF model has the wireless transmitter/receiver built in, so if you plan on having any wireless zones, it will save you from having to buy the wireless transmitter seperately.
The Networx systems come in 3 main "flavors". NX-4, NX-6, and NX-8. The number indicates the number of hardwired zones the panel supports without the need of an additional add-on card. The NX-4 has support for 4 hardwired zones, and the NX-8 has support for 8 hardwired zones, etc.. I would highly recommend the NX-6v2 or NX-8v2 (v2= version 2; fixes some minor bugs that the original models had)
The system consists of the control board, a power transformer, backup battery, siren, and one or more keypads (NX-148E RF recommended!)
Then you can purchase wired, or wireless contacts for doors and windows, and any motion sensors, glass break sensors, smoke detectors, etc.. to go with the system.
As far as motion goes, for this system I would recommend the NX-481 Pet immune wireless motion detector. Works great at eliminating false alarms. It's wireless, so it will require the wireless setup. (remember, if you get the NX-148E RF keypad, you're set for wireless)
As far as monitoring goes, check out
http://www.nextalarm.com" onclick="window.open(this.href);return false; Their service works over your internet connection through what they call an "ABN" which is nothing more than a modified Linksys VOIP router that is hardcoded to communicate with their monitoring station. It works great, I've been with them for several years with no problems. Since it constantly maintains communication, you can have it notify you anytime your internet connection goes down, or the ABN loses communication with the monitoring station. No landline required, cheap monitoring prices, and no contracts! The only caveat is that they do not support your alarm system like ADT or Broadview would, so you are on your own for programming and any support issues. It's perfect for a do-it-yourselfer...
If you're a technical type person, it's really much simplier than it seems. If you need help or have any questions, let me know. I know these Caddx/Networx systems pretty well now.
DVRs are fairly easy to install and set up as well, but they can get expensive, quick! The options and configurations of DVR systems are plentiful, depending on your budget for the project.
Hope this helps!