GPS PDAs

A new crop of GPS enab­led PDAs and smart­phones is coming along, and I’ll be curious how well they inte­gra­te GPS into their workings. What I would like to see is:

• exact timing (the GPS time signal is quite good, the sys­tem should be able to syn­chro­ni­ze to that)
• auto­ma­tic time zone cor­rec­tion – if you know whe­re you are, you know what time­zo­ne you’­re in
• inte­gra­ti­on with address book (how far am I from a spe­ci­fic address, what’s the clo­sest address in my book from whe­re I am, ide­al­ly sor­ted by categories)
• con­tex­tu­al todo lists – what things do I need to do if I’m at home/at work/close to my nor­mal supermarket/next to a train station

and that’s only just the start. 

Is any­thing out the­re that can do that already?