Gift giving is always difficult. First, you have to think from the point of view of the recipient. What would your friend like to receive?
But, this is a bit of a special gift since your friend is leaving the military, making a major transition in life. The gift is to celebrate that transition and commemorate your friendship as much as as a practical tool.
I'm going to assume that your friend is parting with the Army on good terms, that he has enjoyed his military service and that it's just time for him to move on to new opportunities. I'm also going to assume that you and your comrades are going to miss him but wish him well in his new pursuits. In this case, you have to ask if you're buying him the knife to use or as a keepsake. If it's as a keepsake, I'd suggest you get whatever your unit is being issued, have a custom maker in the area mirror polish the blade, fix it all up, etc., and mount it on a display with a nice engraved dedication, "To Sergeant Bob Smith from your comrades in Unit X, Best Wishes and keep fighting" something like that. Perhaps your unit has some motto or something that would be appropriate.
If it's a knife to use, such as the Pardue suggested, you should still, IMHO, make it special by having it engraved.
Chuck
