Yes, I think it's important to preserve old software, especially from the early days of personal computers. There were a lot of great computers back then, some of which are in my basement (Kaypro 4, Commodore PET, Atari 800, etc.), but the IBM PC is the only one we still use. DOS was an easy choice because 25+ years of backwards compatibility means that they can still be played on modern PCs. Windows XP will play many DOS games even without slowdown software or a SoundBlaster emulator, and projects like DOSBox will keep DOS games running into the Vista era and beyond.
Since I'm already plugging my site (if you don't mind), I also created the
DOS Games Compatibility Wiki as a knowledgebase of how to get DOS games running on modern computers. There are 72 games tagged as working perfectly in Windows XP, another 47 that just need VDMSound to emulate the SoundBlaster, and the other 150+ games list whether you can use VM software (like ScummVM) or DOSBox. Since not everyone has switched to Vista yet, this is still a pretty useful resource.