The majority prefer JQuery, I will try to not impose my bias on you but to answer you question as best I can, I prefer Dojo. Out off all of them, I would say try both of these and see which one is for you. Given my preference for a decoupled UI, Dojo provides the complete box, but JQuery is far easier to learn. Their is an elegance to both so I urge you to do the due diligence and at least spend a week working with both before you make your decision.

Thanks, will do.