Those GPS receivers are known to work with gpsdrive:

Magellan 310, 315, 320
Garmin GPS III
Garmin etrex
GPS 45
Crux II GPS PCMCIA card
Holux GM-200 serial version
Holux GM-200 USB (needs USB to serial support in kernel)
Holux GM-210 USB (needs USB to serial support in kernel)
Garmin eMap
Garmin GPSMAP 295
Garmin GNS 530
Garmin GPS 12MAP
EAGLE Expedition II
DeLorme Earthmate