I love DOS, much better than windows, although UNIX is better than both, which makes LINUX the king...<insert idle musings here>
DOS is simple, effective, fast, and easy to use.
DOS was easy to program for, and the games made for it (Warcraft, StarCraft, Doom, Quake, COMMANDER KEEN!, etc...) are still regaurded as some of the best games ever made. And are without a doubt, legends in their genra. Most of the emulators for NES, SNES, GENESIS, etc... were and are in DOS (although recently some like ZSNES have made windows ports)
DOS had such a huge impact on computers that to this day we still use it in many things we do (even if its DOS emulators now and not real DOS).