The best PDA is currently probably the iPaq 3870.
The bluetooth connectivity feature is really great if you use the PDA to access mail and internet services via a BT-compliant phone - once you've seen the ease of use, you'll never go back to IrDA !
The advantage of the iPaq are their sheer numbers: since they have the largest installed base, there's also the largest choice of add-ons, cards, gadgets etc.
The drawback for Mac-users: connectivity to Macs sucks pretty badly. There's one software that is supposed to do the job (www.pocketmac.net
) but the reviews I read about it were less than enthousiastic. You need to decide for yourself if it's worth the try - but if the quality of the PDA by itself is the main criterium and price no concern, the 3870 should be the prime choice.
BTW, there should be some good bargains out there for this device, since HP/Compaq already announced the succesor product line 3900.