A friend is hiking the AT this year starting mid-March and some friends of his (myself included) plan to hike for a while with him from the start; I reckon I might do a month or so.
Having started in late Feb on the AT once before, in a pretty high snow year for the south, I might be a little gun shy this time. But I'm bringing my Montbell Alpine Light parka, a light rain shell (OR Helium II), Montbell thermawrap vest plus light windshirt as a combo to hike in (might just use the rain jacket for that). Goretex socks, PL-400 mitts with eVent shells. Might bring rain chaps and rain skirt, as the combo is pretty light, and can always mail stuff back home.
Going with a 20F bag, but the parka plus a pair of down booties augment that quite a bit.
Base weight is looking to be about 18 pounds (!), but I should be plenty warm.
Downside is that some or all of my hiking friends will start out in better shape than me (a couple are hiking the Florida trail right now ...), so it's probably going to suck getting my trail legs at their pace! :-)