Edited to note that this list specifically addresses pesticides and not other issues such as GMOs. Here's another list focusing just on conventionally grown fruits and veggies. It has one contradiction with freethinkingmom's list but other than that they jive prety well.
apples, celery, grapes (from Chile), green beans, peaches, pears, potatoes, raspberries, spinach, strawberries
asparagus, bananas, broccoli, cauliflower, cherries (from Chile), corn, onions, pineapple, sweet peas, watermelon
This list comes from the Environmental Working Group and I should point out that it's based on government data of pesticide residues.