My experiences: traveling in Europe and Eastern Europe so far....I have ridden this year in: Germany, Switzerland, France, Spain, Portugal, Italy, Slovenia, Croatia, Albania, Kosovo, Macedonia, Greece, Turkey, Georgia (Joe Stalin, not peaches), Bulgaria, Serbia, Austria without incident.
Most hotels will have a place to leave your bike near the front door or in a garage. Or in their lobby! In some cases I left the bike on the sidewalk in front of the hotel. Never had a problem. There are probably some places where your bike (not mine, it's an R1200GSA) may be at more risk, but I wouldn't be riding there anyway. I take the expensive stuff out of the alum. panniers.
Regarding insurance: You can get a "Green Card" insurance doc for most of Western Europe for $120-$135 per month from ADAC for example. For those countries that are not included you pay at the border for a policy. Costs range from $5 Euros to 50 Euros (fucking thief in Macedonia) for 2 weeks to 30 days. This is all for third party insurance, meaning it covers you if you hit someone or something and have to pay them. It does NOT cover you or your bike. That will require you get separate breakdown insurance and medical insurance (ADAC for example). The med insurance cost me 45 Euro for a month. The breakdown cost me something like 100 Euro for 12 months and includes towing to nearest repair, etc, jump starts, gas, general screw ups and some $$$ for you to stay overnight or travel back to mama.
Lots of folks will have other alternatives and examples. I don't care, this is what just worked for me this Spring Summer 2012 for 10,000 miles of Euro riding.
Good Luck N00b