I hiked most of the AT in 2003 and finished in 2004. I can tell you that instead of sticking to my very strict "acceptable" foods that I'd spent months creating in my food dehydraytor, I was eating like everyone else within 6 weeks. All those meals I'd dehydrated went into hiker boxes. I could get by resupplying from gas stations! And that is sometimes what I did.
I am currently planning and training for a 300 mile AT section hike. My anticipated schedule has me planning to resupply from: a large grocery store (Erwin) hiker boxes/hostel supplies (Standing Bear and Mountain Harbor), and maildrops (Hot Springs and Kincora). I have never *planned* to resupply from a hiker box before--this will be a (however small) adventure I'm looking forward to.
Earlier in this thread someone suggested thinking about your hike as a string of week-long hikes--town to town, as it were. This is excellent advice. No matter how you resupply, it's impossible to always arrive in town with an empty food bag. I managed that ONCE during my entire AT experience. Between trail magic (prevalent during early spring but NEVER to be counted on) and unanticipated zero days, early maildrops can easily be too much or too little. God forbid you should have an circumstance, injury or otherwise, that takes you off the trail. But it does happen frequently. If you are loathe to think of "all that money spent" on maildrop food, you may want to pass on buying in bulk before hand.
When I look back on all the time and money I spent on making and sending food I didn't eat, I have two ultimate thoughts: 1. I enjoyed the planning--that was a good thing 2. wasting money is a bad thing. So it kind of cancels out for me. Enjoy your planning and preparing. It's as much "your hike" as the hike itself, I think. Godspeed!