Mobile Maps
I’ve been using Nokia’s maps and GPS on my ‘phone for some time. It works well on the road, but has basically no information other than roads (and while the roads data are good, other data such as rivers and railways are often inaccurate). An annoying artifact of the software assumes you’re on a road, and tends to “correct” the computed fix if you’re not. This leads to an illusion of greater accuracy, but ensures poorer reliability[1].
Recently I tried Google’s maps app. It’s very pretty, and contains rather more information than Nokia’s, though it’s also much slower e.g. to zoom/pan. From home it could see two GPS satellites, and computed a poor fix, nearly 200m away from me (I presume it combined the two GPS satellites with non-GPS info – maybe it knows individual mobile phone masts or something). Surprisingly, the fix was consistent: it gave me the same incorrect position the next day. But since that was from indoors, I gave it the benefit of the doubt: surely it’ll do better in the open.
Then I tried it while out walking. No use: it insists on a data connection (does it need to ‘phone home)? Unlike Nokia’s map, which asks for a connection on startup but works fine without one if I hit “cancel”, google’s refuses to proceed without it. Bah, Humbug.
This morning I tried another variant: I fired up google maps at home, then kept it running as I went out. No use: a short way down the road, it lost my WIFI and insisted on a new connection.
So, back to Nokia maps.
[1] A subject I do know about, both in theory (as a mathematician) and in practice (as someone who has done quite a lot of work in the field).
niq's soapbox 
To deconflate matters, you probably benefit from having a network signal to assist the GPS – phone settings will say whether it’s included in order to get a fix. S60-3 comes with a simple GPS-status app that you can use; if it takes one or two minutes even out in the open, you’re on satellites only, while with network assistance it’ll get you to within 20m maybe in 10s or less. (Up here, network-only gets me to 3 miles away, with a 3km error-radius, quite consistently, until GPS kicks-in.) Presumably the need for an ongoing connection is in order to pull data down from google to show the background map for you; I do know Nokia-maps caches data up to a proportion of your SD-card’s capacity, but don’t know about google-maps per se; given its performance on Android this afternoon, I think it does not cache at all.
When I was using my n95, I observed a most annoying change in nokia maps. v2, or whatever it was that came with the phone, was usable – there was a navigation mode whereby one did not have to download audio turn-by-turn instructions at great cost, but it would calculate (and re-calculate as time went by) the route required, and keep up with me on the road.
I have all-the-interweb-you-can-eat-for-£5 on my tariff (was with 3, now with yodafone); it comes in handy when you’ve just driven 272mi over 8hrs, viewed a house and taken lots of photos.
Oh – other thing you might find useful: nokia sportstracker. Unlike either n/maps or g/maps, it makes offloading and uploading of GPX/KML tracks possible, even comparatively easy. Newer versions seem to include g/maps backgrounds as they go along too.