You can get a networked printer significanly cheaper than $1500, especially if you're willing to buy a used one on eBay. I picked up a Laserjet 4SI/MX with a duplexer, a Postscript card and a Jetdirect card for $150 a couple years ago.
I've even seen new networked laser printers on eBay for < $1000 pretty much every time I've looked.
As far as the original question is concerned though, you will likely see a substantial improvement in speed simply from going from parallel to USB. ECP/EPP parallel ports are theoretically faster than USB 1.0/1.1 but when the rubber meets the road, the USB solution is almost always faster while utilizing less CPU.
Hope this helps.