I have been building models since I was 5, but didn't do the usual hiatus thing after discovering girls and cars. I started off with the usual WW II aircraft/post war jets and monster kits as most kids did back in the 1970s.
I got a Tamiya M3 Lee for Christmas when I was in 6th grade, and it opened my eyes to the world of 1/35 armor. I went through a "Tamiya phase", first trying German WW II armor, then gravitating to modern MBTs. Back in the day there wasn't much, especially Soviet stuff, so after building all the MBTs I could find, I switched to 1/48 Vietnam jets in high school.
When Star Wars hit the big screen in 1977, I became a fan of those awful MPC kits. Star Wars was instrumental in sowing the seeds of my interest in scratchbuilding. Up to that point, I never dreamed of making something that didn't come from a kit. The Shep Paine leaflets in Monogram kits certainly impressed me, but it was Star Wars that gave me the push to actually try something. I did make a couple of Star Wars models from scratch, but it had a broader influence in me in the years to come.
The "end" came during college, when Japanese anime kits began to appear. I got my first Gundam kit in 1983, and it's been all downhill since then. 
We were lucky here in Hawaii, as we got a lot of the kits well before the shows began airing on US TV. I got into Macross after seeing what looked like F-14 Tomcats with arms and legs, thinking they were the coolest thing since digital wristwatches! This was at least a year before "Robotech".
As if to seal my fate as a modeling outcast, I got into Luftwaffe 1946 when I started working. The first injected kits were terrible, but the quality steadily improved and the bigger companies joined in to cash in on the craze. It was during this time that I joined IPMS and cemented my reputation as the guy who built "that weird-a** Nazi sh*t".
Just as the 1946 thing started to cool on the market, Bandai began their Master Grade and High Grade Universal Century kits, so it was back to Gundam in the 1990s.
Today, I build (or at least buy) an assortment of all the stuff previously described, except for the monster kits - I finally outgrew the "glow in the dark" feature.
I am also "F-1 curious" and have a bunch of Wingnut Wings 1/32 WW I aircaft, all carefully selected to have minimal rigging!
I have always liked unusual subjects, and with the selection we have today, the unusual and exotic has become commonplace and easy to get, which I love to no end. I remember when good kits of late war German aircraft like the Ta-152 and He-162 were non-existent until Trimaster/DML opened the flood gates in the 1990s. The fall of the iron curtain also brought a welcome flood of Soviet aircraft and armor subjects. It is a good time to be a modeler!