Permethrin treated clothing is the best deterrent I've used. Deet doesn't do much in my experience but if ticks get on pants treated with permethrin they get off as quick as they can. I've use this spray to treat my clothing before going out in the woods anymore: http://www.rei.com/product/768970/sawyer-permethrin-pump-spr...
One thing to be very, very careful of with permethrin-treated clothing is that it's very water-soluble, and extremely toxic to fish. If you go swimming while wearing permethrin-treated clothing, you will leave a trail of death in your wake, and not just of the bugs you were hoping to kill...
I feel compelled to note that it's also quite toxic to cats (but not dogs). This is one reason you should never use flea products intended for dogs on your cat.
