I had a palm Vx, M505 and am now currently on a Sony Clie TG-50.

I must say the Clie is superior to the palms I had in the past. (Don't know about the newer models though).
I keep in it:
1. Medical Drug Reference
2. Medical Text reference (Clinical Medical Consult in Isilo)
3. Database files - some patient's records
4. Chest X-ray/ ECG references in Isilo format
5. USAF Survival Manual in Isilo format
6. Various medical calculators
7. Loan calculator
8. Lots of jpg photos of my family
9. MP3s for when i'm bored
10. Electronic NIV bible

Memory is boosted via a 128M memory stick!