Currently, I'm a copy editor in one of those new-fangled pub houses that do stuff mostly in e-form. XML docs supported by lots of graphics of all sorts including 3D models. It's not as fun and sexy as it sounds.
Formerly, I was a US Marine (1995-2001), MOS 1833, Assault Amphibious Vehicle (AAV) crewman. I left the Marines an E-5, with some medals, paperwork and an honorable discharge. Good life experience and I still keep in touch with the Marines I served with.
In scale modeling, my preferred subjects are mostly post-WW2 military subjects in armor and aircraft, whatever's fun, personally relevant, and memorable. My family has served in the military since the US Civil War, so we gravitate towards military subjects mostly, but it's always fun to go with purely fictional subjects like sci-fi or fantasy.
Keep the stash small so you can actually build! Spend the modeling cash on good tools, which help you build!