Defining the classic car is a tough one, especially with all of the interesting cars of the last few decades. Its sort of like antiques; there is a difference between an antique and something thats just old.
I've put a lot of thought into why and its difficult to articulate. But, when I think of "newer" cars that are classics I would include the early Miata.
On the same list I would put the Mitsu/Dodge Starion/Conquest, but not the Daytona, the 944 but not the 968, the 928, but oddly I can't find a reason to say a newer 911 or Boxster is a classic, its just a Porsche, the 3rd gen Rx7 and predecessors, the Supra, the VW GTI and Scirocco, and even the old Eagle 4x4 hatchbacks and wagons of the 80's.
But here is where there is a line, just like the difference between an antique desk and an old desk. Some cars are vintage and classic, and some are just vintage, they represent a time and place in automotive design and engineering that is worth remembering but not particularly memorable. It may be worth remembering because of what was happenning at the time or because of what we were doing at the time they were made. Its like last summer, I spotted one of those weird Oldsmobile Omega quasi-hatchbacks of the 80's. It was absolutely mint, no dings, perfect paint, all original as I remembered them.
Was this a classic car? No, but it was old and well looked after, it was what I would call a vintage car. I thought it was cool as hell, too. But, its just not a classic car.
Anyway, bottom line, I suggest that the definition of classic car be liberally constued for the purposes of the magazine and this board. I can't see any benefit in limiting it, and I know everyone here loves cars and can appreciate all kinds of them, even the Omega...It looked just like the Citation...