The best is still DEET and preferably in lotion since it's easier to apply and doesn't penetrate the skin as much. 3M Ultrathon is the best but it's not allowed in Canada because it's more then 30% DEET (I think it's 33%) but I go with Watkins which is 28.5% DEET lotion.

Don't forget to apply your sunscreen about 30 min before, then the DEET lotion, then reapply sunscreen as needed. I think the Ultrathon lasts for about 8 hours and that's one of the reasons that DEET lotion is prefered.