What currency is best for cuba?

I have been told to take holiday money for cuba out in uk sterling to change when i am there. although i realise that cuba and america have their differences, i have always found the rest of the world preferes to deal in dollars over anything else, so which should i go for?also, can travellers cheques easily be used over there and should these be sterling or dollars?
Answer
I am from the uk and went in june and took sterling. they charge you extra for changing dollars dont take them, first you will pay to change pounds to dollars then to change dollars to pesos. they prefer anything except dollars. take sterling and you will be fine. referring to the below comments, things have changed a lot with the introduction of the tourist peso the (cuc), in the whole time i was there i didnt see any dollars at all. read the home foreign website it tells you not to take dollars. http://www.fco.gov.uk/servlet/front?pagename=openmarket/xcelerate/showpage&c=page&cid=1007029390590&a=kcountryadvice&aid=1013618385839