From when I was 4 to about 11, my collection mostly consisted of Star Wars, Bionicle, and City sets, with occasionally the few medieval/Kingdom/Castle sets that came out. My Dark Ages lasted until 2 years ago (I was 16 then), in where I started buying more Star Wars sets, and eventually the LOTR and Superheroes lines.
Fortunately I've never gave away any of my Lego so I had a ton of stuff left when I got back into the hobby.