I think the Leatherman is a good idea, especially if you can get it engraved. I don't have one, but I know tons of people who use them all the time. I'm at the point in my life where whenever I'm doing the kind of work that requires one of the tools in the Leatherman I'm also close enough to my tools to just get the right tool.
Depending on your budget, some kind of men's jewelry--chain (probably not gold, but you could get a nice silver chain), a watch, or a nice wallet would be appropriate. My wife and I received a nice pair of copper (or are they brass?) beer mugs for being in a wedding, and we still have them.
When my son got married he and his wife gave each of the groomsmen individual gifts, which was also quite nice.
Or--and I know this is way out there, and probably will meet with its deserved share of derision--matching tattoos. You could make a whole event of it when you all go in to get your ink. Obviously you really have to know how this would play, but at least it would be different.