It depends on the meat. As Zhizara points out, roasts, as long as they are thawed out all of the way through, don't make much difference, but I warm up pre-formed hamburger patties to room temperature. If they are still cold in the center, they take longer to cook through on the grill or the skillet and I seem to get a lot more bloody juice leakage.
Ground beef that is going to get broken up and fried or baked, sliced ham, bacon and pork chops I keep cold until cooking time.