An often asked question is which ["GPS"] device to buy and which GPS antenna's to buy. I'm not an expert on either but general wisdom seems to suggest that the Garmin GPS devices are pretty decent and that the "Mighty Mouse 2" GPS antenna is good. One nice thing about the Mighty Mouse 2 is that it comes with a universal antenna connector so it'll attach to pretty much any GPS.
If you are just looking for a cheap GPS to use with only your PC, you can get a Rand Mcnally GPS with their software for about $75. It hooks to the PS/2 port of your computer for power (with an optional lighter adapter) and the serial port.. All it does is spit out NMEA data.. No external antenna connector, and initial acquisition time is pretty bad, but it works pretty good otherwise.