I've been interested in trains since I was a little kid.  My grand father had O (that somehow vanished when my aunt and uncle moved him and my grandmother) and my father had HO, primarily Tyco.

Some of my fondest childhood memories were of my father's layout in the kitchen and later the entire living room of the apartment that would become my grandmother's (on my mom's side).  They were just brass track carefully screwed down to plywood and yes, they were Tyco... but it was awesome.