I should really wait for the sales to buy stuff ( °-°)
p.s. I've actually played pretty much all my games except maybe 1 or 2, but it seems it only counts those played online at least once. Also I've got some games at a lower price or free during special events (like Humble Bundle, giveaways etc.), with steam market money or being gifted by friends but I think it considers them as if you brought them.