Exactly! They will respect classic games if they get to know them BEFORE games like Oblivion or Quake 4 for instance. If they get Oblivion as their first game, they will just laugh at Pong or Elite, or even Diablo 2 or Duke Nukem 3D, which is unforgivable.
I agree, don't force them to play oldies, just give them the diskette(if you still have a floppy drive that is) and tell them there are great gameS(!) on it. They will surely go and find out
Just make sure you don't get them GTA4 before they can appreciate the classics. And still, there are one-of-a-kind games amongst the classics that have no sequels or remakes, like Gangsters, the only mafia strategy game out there so far...