Depends on how old counts as "old". I almost never play 80s and 90s games anymore except for when I occasionally go back to play childhood favorites. The only reason I'd go back to check out a game I didn't play is if I'm interested in its significance to the genre or if I hear that it still stands up today. However, as far as I'm concerned, very few of them hold up today, no matter how great they were at the time.
I do, however, enjoy playing a lot of games from about 2000-2010. Most of my favorite games came out during that time, and I still find plenty of great games whenever I go back to play ones I missed. There's also still a lot of games from that time that I still want to get around to playing, and I'm constantly adding to the list.