personally? It's the history. Who wants to build a P-47 if they don't know what it even was or capable of? Most other kids I know could care less, though I have 2 friends that enjoy history. 1 of them builds lots of models. Now I love New dragon releases but that's just me...
oh, and video games... I've found a lot of inspiration for models through games. I've been looking at making different vehicles and figures from the Halo series and Star Wars video games. Plus I found new motivation for WWII AC after playing Secret Weapons over Normandy...