I'm hiking for about a month on the AT, starting just a few days before you, so I'm mentally dialed into this a bit now.
Overall a great list IMO. And your "winter" baseweight is well under mine, so bear that in mind.
Swapping to a lighter pack is an interesting approach; not a bad one on the AT. I'm using a Circuit myself for my ~month hike.
I'm personally not a fan of rain pants, but am bringing my light rain chaps on this one. 10 oz for rain pants seems like a bit of a hit to me, however. I'm actually bringing both chaps and rain kilt, but each of those is 1.7 oz, for a total hit of 3.4 oz, and one or the other can be mailed home separately if desired. It's admittedly not, however, a great combo to wear while washing other clothes (I also carry a light set of shorts that double as spare underwear).
Alpine Light Parka --- I own this very same item and ALMOST brought it. Looking at recent weather trends, I will instead bring a combination of R1 hoody and Ex Light down jacket. Definitely not as warm, but a flexible combo, can use the hoody on-trail. I really liked the Alpine Light Parka when I started the AT in late Feb in 2010. But the weight and bulk of some things I brought then were more than I think I'll be able to get by with starting this year March 12th.
Glove liners and rain mitts however --- you might want something more for your hands (?). I'm bringing just those things AND a pair of OR PL 400 mittens.
Shoes or boots? Bring a pair or two of breadbags if so; handy I find to put on dry socks and keep them dry for walking around in camp. Which I tend to do more on the AT, it's a more "social" trail.
Thermarest xlite --- warm enough for your start? Consider getting a 1/8" gossamer gear thinlight pad and putting it on top for the colder nights. Put it underneath on the other nights as I personally don't think that a polycro sheet will help protect from irregular shelter floors all that much. Could reduce "wearing out", but anything that could puncture an inflatable will go right through the polycro.
Why are you carrying a power cords for ipod and nook but not the items themselves? I'm not suggesting that you should carry the items ...
I do find that a very light standalone (single AAA battery) MP3 player is worth carrying, but wouldn't consider a book reader. The AT is a social trail. I can read on my phone if I want downtime in a motel or hostel.
How will you carry your phone? Keeping it handy (on a pack strap) is important to me, as it's my camera among other uses.
Deet: won't need it for a good while, can always buy along the way when you do.
Something to dig a cathole with?
You could swap out your headlamp for something lighter once you get to, say, Pearisburg.
Have a great trip!