I'm currently using the PalmOne Treo650. For me it is the best pda/phone in the market today.

I've been a palm user ever since they started (3Com pa noon), from Palm, Palm III, IIIc, Palm V, Palm Vx to Tungten T, Treo 600 and now Treo 650. I love Palm OS for its simplicity and ease of use. Also, lots of applications available on the net.