I buy annual travel insurance in the UK, it costs around GBP£50/US$90 a year and covers all my baggage against loss/theft worldwide. More importantly it covers medical/legal bills worldwide, up to GBP£10million.
On a cautionary note, my (American) girlfriend never takes out insurance when she comes to the UK. I have warned her many times, but if she (God forbid) was seriously injured in the UK and ended up in ER she would be in for a medical bill comparable to the <b>full</b> bill at a US hospital.
Young (<26) people can, I believe, take out such insurance at very reasonable prices at statravel.com if you are over 26 I am fairly sure AMEX offers insurance for baggage/foregn medical bills. If you are business traveller, I reccomend your carefully check your company's insurance policies.
I don't want to be handing out a lecture, or preaching to the converted, but a lot of my american (college age) friends neglect insurance of any sort when they travel to europe and as we all know **** happens, so it pays be prepared, no matter how many trips you take/ have taken.
I speak from the experience of having my passport stolen in Pittsburgh. Luckily I was able to drive to DC and get an emergency british passport issued and still make it back to PIT for my flight. In any case insurance covered the cost of the travel and replacment passport in DC, if I had missed the flight I would have been covered for getting a later flight. Uninsured? I'd probably be stung for the full Y fare the next day.