I think a lot of hunters either climb WAY too high, or else don't know what 30' up really looks like. I hear all the time about how you have to go so high up to get above their scent... not true at all.

Jeff pointed out several good things... most importantly back cover, which is in fairly ample supply this time of year.

One other thing that is important is not going so high that your shot angle is too steep for a good kill shot. Its hard to get both lungs when they don't overlap in any spots (in fact its impossible). I have found that anywhere from 10' to 17' feet (usually 12-15') from the ground to my boots is about ideal... again, based on back cover.