I have a Garmin GPS Pilot III that I keep in my flight bag and use once every few flights to stay current with it and keep extra batteries. I like it very much for aviation, and have seen a non-aviation version (the exact same thing, price too) that had more roads and landmarks that the aviation GPS doesnt have (Aviation GPS has runway info, frequencies, services ect ect...all nice)
I dont know what it's called, maybe GPS III, but it is a good reciever and will run you about $500.
There are lots of lower-end items out there and lots more higher end items out there. You can spend anywhere from $80-$15,000 on a GPS/Navigator that ranges from basic handhelds to super sophisticated do-it-all-doodads for airplanes.
I'd recommend Garmin because its what I have and have good reception and no complaints.