I use mine where there is free wifi, which is quite common throughout Europe. I have yet to stay in one of the hotels that had no wifi, but I have had a couple that had to give me a wifi base to use with their wired connections.

I also use 3G as a backup in several places using either a local prepaid card or a MaxRoam chip as a last resort. I rarely must use the 3G for very much time, but I always seem to need it for a couple hours or so per week.