12. Old game that I still play - Well, all of my games are "old" versions and this is is similar to Day 5's answer: OD&D (1974 w/out supplements) + Chainmail (3rd ed, 1975); Traveller (1977); AD&D (1977).
Why do I enjoy them so much more than more modern versions? That's a hard question to answer because all of my answers come down to "I just enjoy them more." I can still find great players who want to play them! And that's enough for me.