When it comes to "modern" armor, I'm in the same boat as Rob.. 29 &1/2 years of Regular Army and Army National Guard service... I build lots of dioramas, and most all of the stuff I build with the modern armor kits as a focal point are based on things I did and saw during my career, some peacetime Army, some combat... I tend to be rather dark with the combat scenarios though, so I do more peacetime Army stuff, which basically hows just how Gs live in the field, around, on, and in their vehicles... Folks that have never served don't see it, that is, just how a crew makes a 32-ton tracked vehicle a "home"...
I also do "funny stuff" dioramas, things like the "M151A2 Foxhole Detector"... That dio had it's roots in an FTX in which the Battery Commander's driver drove the 1/4-ton into an old two-man fighting position one night, burying the entire front end in the hole, throwing him and BC outta the Jeep and then ending up on their butts in front of the Jeep.. (It was a night-move, they were driving with black-out markers, and no night-vison, and going about 3-5 mph, so they weren't hurt)
We couldn't pull it out with the M880 (That's the old Dodge pick-up CUCVs), so we had to radio the Battalion Maintenence section to get the Snoopy up there at first light to pull it out.. ("Snoopy" is the M578 LARV we had, and gets it's nae from the "doghouse" on top of the hull)
"Snoopy"
I tend to do more WW2 armor than anything though, and tell stories with that, too.. I especialy like taking Bill Mauldin's "Willie and Joe" characters and making "3-D" versions of Maudin's cartoons..
Fer instance...
And my version:
You get the idea...
Anyway, that's what I do, that's my story of how and why I pick what I pick... Many times I use the same kits, since many of the stories are about the same guys, or crews... ( I have 9 Tamiya Jeeps in the stash just for "Mauldins")...