in one of tschicholds writings i remember him pointing out >>a good type designer can design with only one typeface<< ... if you had to design various things with only one typeface, what would be your choice (and why)? gill sans, futura, helvetica, garamond, ... ?
mine would be gill sans, i really cant say why (sorry), i just love it.
but i have to admit i couldnt live without just one typeface, too ... i'll try not to wonder about your "one car" and "one house" - seems typofonderie is doing quite well? ;)