One of your most important considerations before you travel. The type and level of travel insurance you need depends on where you are going and what you intend to do. For example, you may be intending in participating in what are considered to be more risky or extreme activities and therefore you want to ensure that your travel insurance covers such things. You do need to do a little research in this area as some insurance types limit the number of days you can be away from your home country for and what you are allowed to do whilst away.
We cannot tell you what insurance to take and with whom but you should certainly do some research in this area and if you are unsure speak to someone who is qualified to advise on travel insurance or someone you trust who knows about it. Do make sure that you read the small print so you know exactly what you are covered for and any restrictions that apply (perhaps for example dangerous activities). Make sure your cover is comprehensive and that there is good provision for emergency repatriation should you need it (hopefully you will not need it, but you want to be covered just in case). Ensure that the insurance company provides you with a telephone number to call in case of such emergencies. Ensure also that you understand what the policy says and what you should do in certain situations. If you don't understand then contact the insurance company and get them to explain it to you clearly.
There are lots of companies and banks that offer travel insurance these days so it is a very competitive area. You will probably want to go for the cheaper options, but do not disregard good quality travel insurance because it costs a few pounds more. Usually insurance comes with policy excesses and check these before buying. It means you have to pay the first £xxx before the insurance company will pay out on something. Some of the areas that you may want to consider as essential to be a part of your travel insurance policy, apart from the very necessary medical emergency repatriation and medical cover whilst travelling (to make claims should you receive treatment whilst abroad), could be lost/stolen baggage insurance, trip cancellation, extreme activites, and number of days per trip coverage (it is very important you check this if you are travelling for a significant length of time as some travel insurance policies limit trip lengths so you may need a more specialised policy - check with the insurance companies for further information). As you can see there is lots to consider and different policies offer diffent combinations of things. It is very important that you choose the travel insurance policy that is right for you and your particular circumstances so choose carefully to give yourself peace of mind.
The following UK website provides some excellent impartial advice and guidance on the best travel insurance for your circumstances: Travel Insurance Guide (UK)