How many of you have actually tried playing your old favourite games lately? A year ago I would have said that I still have a warm place in my heart for the original Command and Conquer, because I played it so much when it first came out. But rose-coloured memories are often better than the real thing. When I finally got the original C&C running again, I realized that it's ... well ... lame.
Don't get me wrong, it was a big deal for its time, but it's 2009 now, and nostalgia aside, it's a terribly lame game compared to newer RTS games or its own sequels. Same goes for Master of Orion 2, which I used to think was so great. It reminds me of those old movies from the 1950s and 1960s which are considered "classics", but which, if something with that kind of writing and acting and direction came out today, would get lambasted relentlessly.
There are some older games which still hold up well. Command and Conquer Generals: Zero Hour still holds up well, in part because so many RTS games have gone the micro-managing "let's see who can win the clickfest" route at the behest of people who call themselves "hardcore gamers". Also, I still play Unreal Tournament 2004, which still gives us most of the gameplay of UT3 but with the advantage of working on crappy hardware (by today's standards). Another set of games which holds up well IMO is the Total War series: I can still enjoy a game of Rome: Total War, Barbarian Invasion, or Medieval 2: Total War, in part because of the many amazing user mods that have been released for them. The Third Age mod for M2TW, in particular, must be seen to be believed. It's a "Lord of the Rings" total conversion mod, and it's just amazing.
The PC modding community can often be instrumental in keeping old games alive.