I've used Worldnomads in the past for my travel insurance, and found them pretty good - though of course I thankfully didn't have to make any claims for lost luggage or anything more serious, so can't comment on that side of things. Pretty easy to get signed up, and covered with worldnomads though, and I first found out about them through lonelyplanet, which I trust.
We're about to travel from here in the US on a 4 month trip through Europe, and would love to hear your recommendations on travel insurance plans and pitfalls? Thanks everyone