I use a TDS Recon running Mobile 5 using SoaringPilot with a Styletap
Palm emulator.
The GPS is a GobalSat BT-338

Next time I'll get the PDA with an SD card to save me having to hook
up the PC to get the igc files. There's a bit of fooling around to
figure it out the first time, but if you're over a 5 on the 10 point
geek scale it's ok.
The GPS has 10 hours (at least) of battery capacity. It sticks to the
bulkhead behind me with Velcro. It's flawless.

The other day I forgot my GobalSat GPS and used my Garmin 76S, set up
with the distance and "idiot arrow" to the next waypoint. If you want
something foolproof that's the way to go. I've also used that as a
receiver connected to a Palm "T" by wire, but that's two lumps in the
cockpit.

Zero RF issues.

Both these setups make igc files good enough for the OLC. (anybody at
your club will know if you're cheating anyway)

Martin