I have a couple of ideas, but nothing really outstanding. We have 2 sons in the service, one Marine and one Sailor. The Marine is being deployed in January to Iraq, and the Sailor's ship will be deployed for 7 months, starting in February. The sailor also has a girlfriend in the Air Force, who will be deployed to Iraq in March.

Any ideas for this bunch?

For entertainment between missions:
Books, MP3 Player, CDs (full of mp3s purchased legally), DVDs, video games (if you know they have a console available).

Useful:
Knives (Gerber Gator is nice), Multi-Tool (Leatherman, Gerber), nice pens, notebooks / envelopes / postage.

Phone cards and regional junk food as stocking stuffers.

Since they are such close family members this probably won't help you much but my BIL who was deployed in October told everyone not to send him gifts for Christmas or if we do send stuff he can share. He said when he was over there at Christmas 2 years ago that he felt bad for the people who didnt get anything for Christmas so he gave most of his away.

I don't know what we'll end up sending that he can share but we are donating money to a charity he does work with in his name or maybe one of the programs that they do here for the kids who's parents are deployed (BIL and SIL don't have kids yet but he loves kids and does a lot of stuff with underprivlidged kids)

Sorry not much help

Melissa