GoKnowing.com recommends InsureMyTrip for buying travel insurance online. The site gives you the ability to compare, side-by-side, a wide range of insurance companies and policies. This way you can find the insurance policy that is best suited to your needs, without being forced to buy insurance for things you don't need or want.
When traveling overseas, it is important to always be prepared for the worst. Anytime you are traveling overseas, you should make sure that you are at least covered for medical expenses. If you book your trip with a credit card, it is worth calling your bank and asking about any insurance that your they may cover you for (this is more common with gold and platinum cards).
Insurance coverage in case of accidental death (they don't cover you if you kill yourself deliberately) is something worth thinking about. If you are killed at some point during your travels, it can be particularly stressful on families if they are forced to pay to have your body flown home or cover other expenses that may arise from your death.
Many people also like to get coverage for their belongings. If you have a camera, a laptop, or even a family heirloom that you would be distraught to lose, knowing that you have financial protection against their loss, theft, or damage can be a big relief and help you really enjoy your holiday.
You should be aware that many travel insurance companies will offer you insurance on any trip that you arrange, but some set a limit of only paying out a certain number of times in any given period. Many regular travelers either have insurance plans that allow them to claim more regularly if necessary, or are careful not to claim for the small things, as they could potential void a large insurance payout on a subsequent trip.