A'ight. Your 19" monitor will work, if it has a standard 15-pin VGA connector, with no adaptor. Apple actually uses mostly standard hardware.
Unfortunately, for a professional system, $1,500 is on the low end. I paid about $4,000 for my Power Mac last year, $3,100 for my PowerBook, $1,700 for Jenni's iMac, about $1,500 for my iBook...
My Power Mac is a dual 800MHz G4 with a GeForce 3, 2x60GB IBM HD's, 1.152GB of PC133 RAM (2x512 & 1x128)... has 2xUSB 1.1, 2xFireWire 400, an AirPort card, gigabit ethernet... it's pretty awesome. It runs Mac OS X great (Photoshop, Bryce 5, etc). It was actually ordered on September 11, 2001, and I've already said what it cost. Fortunately, you can probably find one on eBay for about... $1,500

and if not, I might be willing to sell you mine (I was thinking about upgrading anyway).
Anyway, search eBay for Power Mac dual 800 or something. I'll do the same and post you some links. Also, places like smalldog.com might have some refurbished PowerMacs, which still come with the standard 1-year Apple warranty (and the option to extend it to 3 years).