If he improves a bit, or even keeps going the way he has been, Ndamokung Suh will be the cornerstone of that Lions defense for a long time. And one of the best DTs, ever.
Although Warren Sapp didn't make it, either, so maybe it's more of a longshot to be "great" at that position that I imagine.
Ed Reed was already on it and I doubt he'll go much higher than he is now. He's not exactly on a steep decline, but he's not getting any better, either.
Patrick Willis is someone who's bound to make that list, as well, eventually.