Hi,

I'm about to head off overseas for a month and will be travelling through a lot of different countries and was interested in getting a GPS unit to help me get around.  Quite a few countries / cities to take in (London, Oxford, Paris, Genoa, Marseille, Barcelona, Casablanca, a few islands in the atlantic and carribean, and finally miami and LA)

I'm a total GPS n00b.  Brands I read a lot about are tomtom / navman / garmin
I'm not wanting to spend a fortune on maps that I'm probably mostly only going to use once if I can avoid it - will mainly be using the unit in NZ and Aus after this trip.
Are there decent open source city maps (especially for LA) or do you have to pay a fortune for each set of maps?  If you pay, do you get 'free' or cheap updates?  If I sell the GPS unit - can I keep my maps (if I upgrade) or are they tied to the unit somehow?

My only real experience with GPS was with a friend that had a garmin unit that he bought in australia, purchased the NZ maps and away he went.  Seemed easy enough to use.  Had things like current speed, average speed, distance travelled, places of interest, decent zoom in/out of maps, route planning.  Plus a few extras - mp3 playback (either from the unit or he hooked it up to his rental car stereo too somehow) and USB + SD Card reader (presumably for maps) but he had photos and I think movies (divx?) etc too.
I liked that it was a nice blend of big screen, but not a huge unit if you wanted to pop it in your backpack or laptop bag.  Battery life seemed not too bad (but it was very new) and he kept it topped up with the car cradle.

Price?  I've no idea what these go for, but I'm guessing anything up to $900 would be ok - maybe a bit more if the features warranted it, or am I wildly off the mark on price vs features?

any suggestions on what I should look at?

cheers in advance..