Via the USO in my city (my office is sponsoring them for the holidays):
Drink sticks (Gatorade, Crystal Light)
Instant coffee single serving packs (I found apple cider too)
Applesauce and pudding cups
Chicken and tuna in the fresh pouches
Chex Mix, Gardettos and other portable snacks
Easy Cheese (I found this one funny)
Gum
Tootsie Rolls (mmm chocolate without the melting!)
Hard Candy
QTips
Chapsticks
Hand sanitizer (my husband suggests the itty pocket size bottles)
CDs and DVDs
New Magazines (in case of all media, no porn or other things which could be offensive to the residents of the home country)
White socks
Batteries
AT&T International Pre-Paid Phone cards (good for while traveling to and from area)
Feminine Hygiene products
Letters of support
My husband has also found helpful:
Clorox Wipes to keep things clean
I sent my husband a set of 600 TC pillow cases so he can have a little luxury
Photo album from home (and I asked everyone in the family to send pictures of family events to add to it)
Potato milk (he's lactose intolerant)
Those microwavable brownies in the single serving bowl (he loves brownies!)
I also sent a package of pens and a package of little note pads because I wasn't getting any mail from him--but it hasn't worked.
Along those lines, I read somewhere online where there was a now defunct organization that was designing blank greetings cards for all occasions to send to the war zones so that soliders/sailors/airmen/Marines could have cards to send to family back home. My husband noted that the card selection at his local PX was not great, and its not like they have Hallmark on every corner. I am trying to get my chapter on this.
I also read somewhere online where people suggested sending spices--if your cousin likes Tabasco or garlic powder and he doesn't have a good dining facility, you might send those.
ETA: I know I've mentioned this before but the post office has flat rate boxes that you can mail any weight amount for $8.95! Great for care packages!!!