Heh, mine was also Sonic 2. Well, that was the first one I owned, anyway. I can't remember wether or not I played the first Sonic before Sonic 2...
Incidentally, I make a point of renting every Sonic game that comes out, just to see if it might be enjoyable. Yes, I'm a nostalgic idiot. At least I know it
(as a side note, I thought that the sonic adventure games were quite fun for the most part and that Sonic Heroes, despite being very flawed in design, was still enjoyable enough for me to pay 15$ (CAN) for it recently)