Greg is just the best, whether in the lab or out in the field, I think in the lab he had more of a chance to show off that sense of humor, it's easier to have one in there rather than in the field at a scene, but at the same time, he still has that wit. He's extremely intelligent, and makes one hell of a damn good CSI. My favorite Greg is still Who Shot Sherlock, but of course Fannysmackin' is probably tied because there was such a different dimension shown there. But you have to love Swap Meet just for the scene in the kitchen when Grissom opens the dish washer, the look on his face, plus in the lab later with Mia, it kind of showed that he really isn't the player he says he is, and for me, that is just too adorable and makes him even cuter.
Eric really rocks this role, he really does, he's just excellent and I think the producers and writers made a great choice to listen to him to get Greg out in the field and expand his role, they have to see that that was a great decision.