Buy the system separate from the monitoring - there are ripoffs out there where you get the system "for free", but you pay $30 a month and have to sign a 3 year contract.
I had my system installed - 5 doors, 2 glass breaking alarms, 2 smoke detectors, battery back up and 3 keypads for about $500 and I pay $12 a month for the monitoring. There are also cellular connections you can get if you're worried about the phone lines getting cut.
I honestly couldn't care less if someone breaks in while I'm gone - everything's insured and the "irreplaceable" things like family  photos, no one wants 

 (plus it would be quite a trick to watch someone carry anything heavier than a fax machine up my driveway, hehehe). I have the alarm because my biggest fear is waking up with someone already in the house....I want the alarm to go off so when we're face to face, I have my gun in theirs 
 
 
The smoke alarm connection's good for when I'm gone, but I live so far out, every house in my subdivision has burned to the ground before the FD got there 
 
 
Yeah, I know, living this far out I really don't NEED an alarm, but I also didn't want to say "Sure wish I'd bought one" AFTER someone broke in 
