To start, even for most seasoned ULers, sub 5 on a thru hike is a stretch goal. Weekends its ok, but you will be dealing with lots of varying temperatures, rain, and keeping your mental state satisfied. Your start date will have a lot to do with the gear you carry. Im going to assume a mid April start to keep your weight as low as possible.
Pack- ULA Conduit (~$100-$120), MLD anything. Durable, full feature frameless packs. If your under 6 lbs not including pack, the fanatic fringe thompson peak pack ($80) with a belt may work and be reasonably durable. I used the Conduit thru hiking this year and it was pretty much perfect. For all the rain on the AT, I would use a silnylon pack cover and a pack liner (Gossamer Gear makes a light one), and roll top stuff sacks. Especially if you have down.
Sleeping- A light bivy will be a life saver if you stay in shelters like most people do. Titanium goat, six moon designs, oware, and equinox all have low priced options. The MLD is so light though!
For your bag, Tim Marshall can sew you a synthetic quilt rather inexpensivley ($160 for 5oz XP, recommended) and cut a 1/2 lb. I used a 5 oz XP topbag most of the time and it was great.
Shelter- def. drop the tent. I used a 5x9 sil tarp at 8oz and really cheap. I only used about 12 or 15 times staying in shelters usually. If you plan to camp a lot, a larger tarp would be better. Ti stakes only weigh 1.2 oz for 6, but i sent them home quickly and tied my tarp to rocks sticks and trees almost all campouts
Pad- a new prolite small is 11 oz i think and would add tons of comfort over the z rest. pricey though, but recommended for shelter hopping.
Stove- looks good. I wouldnt opt for a heinekin can for thru hiking, and definitely not for a wood stove. Dry wood will be hard to come by if it was anything like this year. Mini Bic, drop the matches. You should only need 3 liters water capacity tops. The guy i met that went stoveless for a stretch was miserable and we made fun of him (Panama Red).
Of course drop the spot unless someone from home is forcing you to carry it. Cell service isnt reliable, but its not bad. Between someone with verizon and cingular most of the trail is covered.
Clothes- a spare t shirt and light shorts or thermals will be appreciated when you come into camp soaked, as will dry socks. +1 for dri ducks too.
The lightest I ever got was 7 lbs base, and the lightest I saw was 6.5 from a kid not carrying shelter and about 1/4 a foam pad. I was usually around 9-10 lbs and more happy with it than I was at 7. After a while, 2 lbs doesnt feel like anything, but a Big Agnes pad and dry clothes to sleep in feel like heaven.