In every package that I sent to Matthew I sent him a can, or two, of salmon that we had caught and that I had then smoked and canned. It was a "homey" present that I knew he would love. I also usually sent one of the cans of powdered Gatorade, some type of gummy candie (he loves things like gummy worms), I would send sunflower seeds sometimes, snack bars ie granola bars, or protien bars (he has a heck of a time keeping weight....wish I had that problem) I also would add in a written letter and whatever else I had at the time.
I didn't live near a commissary, the closest on was a little over 3 hours away, so once a month or so I would drive up to Anch and would do a HUGE shopping trip - mainly for stuff to send him in care packages, because otherwise alot of the stuff was WAYYYYYY to expensive in AK for me to send to him all the time.
I know a big thing is foot care stuff, whether its insoles for his boots, or foot cream or powder to try and fight athletes foot. Also baby wipes, even the one's that come in the indivudual package. So that they could stick one or two into a pocket in their cammies, and maybe be able to take the time to "wash" their hands before they eat.
I would also do the pillow case with my perfume on it (send it in a plastic baggie so it still smells like you when they get it) on big occasions; ex Christmas, Valentines day, our 6 month wedding anniversary.
I know you wont get to talk with him all that often, but do you have email access with him??? If so ask him questions about things that he would like, find out if he has access to a microwave and if he does - then send him the Cambells microwavable soups so that he has alternate options for food instead of always the chow hall. I sent top-ramen, the little packages of the premixed tuna (for protien) send dried fruits.
And I know how weird this is going to sound.... but tampons! I talked with some girls at a KV course that I did, and one of the ladies husbands unit had been getting the Unisex carepackages from a church group. So each package had a small container of tampons - the guys as a joke decided to carry them with them saying things like, "You got your tampon? Just in case So and So hits his time of month on this mission???" Well it turns out that one of the guys got shot on a mission, and the Doc happened to have his tampon in his breast pocket and it was the first thing that he grabbed and was able to insert it into the wound track. Saved the Marine's life!!!
Of course when the Marine called to tell his mom what happened he asked if she knew that the tampons expanded when they absorbed blood... No one in my class had a straight face after that recall!!!!