I build mainly aircraft (planes & helos) in 1/48th scale, but I'm moving more towards 1/32nd, now that my eyes are getting a little older, and small things aren't as easy to see. I also dabble in tanks (1/48th & 1/35th) plus other armor, motorcycles, cars, and a ship or two in the past. Aircraft interest is just about anything Marine regardless of era, but branch of service and nationality aren't a limiting factor. If it piques my interest, I'll build it. I have yet to try figures/busts or sci-fi.
Gary Mason