Not much experience with these things, however my younger son has just bought the Nokia 6110 Navigator - and I can't get over how good it is. Instructions are timely and easy to understand, it re-calculates very quickly, and even when driving up to Bigdogs place where it stated it's maps weren't 100% (it mentioned something like
\"there be dragons there... arrrrrr\" 
), it still got it right.
It literally tells me as I pull into my driveway that I have reached my destination. Can't beat that, given it does all the \"usual\" 2G/ 3G/ phone/ camera/ video/ MP3/ Mpeg4 functions as well!
Now if I can just get it to use the Ozzy Osbourne voice-over...
