I've got a CF GPS receiver...
What you'll need:
1. GPS receiver. It can be either an external receiver, or a Compact Flash receiver. For car use I'd go for an external receiver. For carrying it around and using it without an external power supply, I'd get a CF receiver.
2. You'll need a memory card for the maps. Depending on what type of receiver you get, you can get an CF or SD card. I use an SD card for my maps.
And of course the software. Check out
www.gpspassion.com for info on GPS, it'll keep you busy for a while...
Good luck! Don't rush it, shop around, and get something that'll suit you. I got my Navman GPS1000 receiver for 75 euro's secondhand. And it works brilliantly, no complaints whatsoever!
Happy hunting!
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btw, it works with tomtom 1.5 and tomtom 2. Very well, I might add... never been lost with it in the car!
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Obs