Well, I find 3G VERY expensive....and coverage is distinctly patchy.
In Germany, you can buy a month's unlimited 24/7 T-Mobile WiFi for about €22 - a much better deal than the €6 per hour you can be ripped off for in many hotels or airports
!!
Whenever staying in an hotel, I always fill out their 'guest feedback' form stating that WiFi access should be free - as it is in most US/Canadian hotels and airports.