[mindfrost82]

I haven't tried Garmin XT, but it sounds pretty good.

iGuidance v4 had the most up-to-date maps I've found for my area, plus the TTS street names it great. You need something like GPSGate to get it to work right with the internal GPS though.

EDIT:

It all really depends on what you're going to use it for. If you want to find local places, then Google Maps and Live Search are going to be the best for that (if you have internet). If you're going to use it for navigation, then one of the apps with preloaded maps on the memory card is going to be best.