Since I'm a poor college student I don't buy many new games. Actually, I think it's been over five years since I bought a game when it first came out. I do, however, still enjoy many old games, and even occasionally buy games for older systems like the PS2 when they're less than $20.
When I went home for Thanksgiving break I took back with me some old PC games, namely Jazz Jackrabbit CD and SimCity 2000 Ultimate Edition. Thanks to DosBox, I've been able to play Jazz just fine (I can't play it in full screen, but hey, not a big deal) on my Windows 7, but SimCity 2000, however, has been a problem. It will run, and you can build a city just fine, but you can't save or load a file. This is a big problem because, while building a city is fun, it's almost pointless if I can't save it.
Interestingly, most of the game speeds in SimCity have a set timing, but I believe the fastest speed is set to run at however fast the processor can run, because once I select the fastest speed, it becomes impossible to change it before the end-of-the-year finances window pops up.
Having old games is great because they're still fun and they're free, it just sucks when they don't work like they used to.