I'm back from Ireland. Using WiFi in my hotel Google Maps actually found my location in Dublin while connected to WiFi, but only in some of my hotels, not all of them. I guess it somehow knew the location of the router or something. Otherwise I could not use the nav or GPS, and i assume that soon as i left the hotel and lost WiFi it would stop working. On a good note, i was able to make Skype calls using the Fring app while connected to WiFi, that came in handy.
Basically the Droid is only good for email, Internet and Skype (via Fring) while in Europe.