Outfitting for the AT - What I'll Wear

An Appalachian Trail thru-hike spans all the seasons. From winter in the mountains of Georgia and North Carolina, pleasant spring weather in Virginia, brutally hot and humid in the mid-Atlantic and southern New England sections, and fall thru New Hampshire, Vermont and Maine.  Snow, mud, bugs and lots of rain.

A Backpacker's First Aid Kit

Anyone venturing into the woods should carry a basic first aid kit.  But what should be in it? Should I buy a pre-packaged one?  Or build my own?