GPS/A-GPS advice needed

Bit of a noob to the idea of having GPS on a phone and tbh the more I have read about GPS/A-GPS the more confuddled I've got

Basically I want a phone that will work without needing to access the internet for the satnav software to work so thats either one where the maps come on a CD or Memory card, or where they can be downloaded once onto the phone and not in a piecemeal format

Obviously I would like voice prompted turn by turn and route planning and the feature or option of speed camera warnings

And I would like the satnav software to be able to continue working even if there isnt any form of phone network coverage which I am not sure the A-GPS system is capable of as it always waffles on about downloading things

The three phones I quite like at the moment are the nokia C5, 6700 and X6 (16GB) but all they go on about is ovi maps, and call me paranoid, but I'm extremely suspicious of a company like nokia claiming to be giving anything away for free and suspect it will turn out to be expensive to use with constant map updates over the mobile network or similar

So any advice on recommended combinations of phone/software or software that would work well on either of those phones or even tips on what NOT to look at

Many thanks in advance

Mike