As others have noted, a lot of the requirements will depend on what he's doing, where he's doing it and the unit SOP.
I wouldn't classify the Glo-Toob as tactical in any sense because you have to hunt for the exact setting - this isn't to say he can't or won't use it in a non-tactical environment, but it probably won't be a mainstay in his pack.
I was sitting guard tower on Anaconda (Balad) from Sep 06 to Sep 07 - you had to have a non-white light, but the SOP didn't specify what color.
The
Inova micro lights were very popular and cheap (about $5 at the PX), but weren't exactly durable.
My tactical/bay maneuvering light was the
Gerber Infinity in Red - pocket clip, center-line lanyard hole and feeds on AA batteries.
For my up close and personal tasks, I wish I'd had the
Arc AAA - small, lightweight and bright enough for most jobs.
I ended up using the
Inova X1 or the
Pentagon MOLLE light in conjunction with the Gerber for non-tactical lighting.
A good personal light is invaluable no matter where he goes because you never know when you'll be fumbling around in the dark, even on Anaconda. You just have to juggle output versus run time versus battery availability.
-Trevor