Globalsat have really made a name for themselves when it comes to GPS hardware (especially with some of their Bluetooth-enabled receivers) and their latest set of product releases show why. First up is their Compact Flash GPS Receiver (BC-337 SiRF Star III). This is great if you don't have Bluetooth or if you want a more integrated solution. For those of you who don't have CF slots in your PDA, they also announced their SDIO GPS Receiver (SD-502) which comes equipped with 512MB of memory built-in (no need to sacrifice the memory for the GPS). Finally, they have their standalone All-In-One Car Navigator (GV-201), which sports a 4" QVGA screen, 266MHz ARM920T processor, and 64MB RAM / 64MB ROM.
On a more personal note, I've finally given into GPS technology myself, having purchased a standalone Garmin Nuvi 350 which should arrive next week! I'll have to let you all know how that works for me once I've played around with it for a bit.
Compatibility is why I use a BT reciever (iTrek M3 SiRF Star III from Semsons). BT is the way to go if GPS isn't built-in to your PPC. it'll work the same with my current WM2003 device or WM5 whenever I can afford to upgrade (if I end up with a WM5 device w/o GPS).