Alarm system recommendations?

[Mark C]

I'm interested in getting a relatively simple, monitored alarm. Doors, windows, fire, the usual. No need for cameras or anything too fancy (though I like the option of adding future home automation). Since the house is fully built, I think wireless options are best.

There seem to be a ridiculous number of vendors on the market for both components, monitoring companies, and installers. Anybody have opinions, good or bad for national companies, or local in SE PA?