I normally stand with my hands behind my back personally, just what I find comfortable though because I do it no matter what type of garment is covering my lower half. However, that changes when walking with my wife at which point I generally have her arm cradled with mine.

I must say that I greatly appreciate Zardov taking the time to post examples. As a very visual learning I was happy to intently study the second one to be sure I had the post down properly.