The only system for which I have in excess of 100 unique games is the Atari 2600 (296), but I can't remember exactly which title pushed me over the century mark.
Anyway, congrats on the achievement. Between 16-bit, 32X and CD's, my Genesis library is the 2nd largest in my collection - approx 80 titles. This is a little surprising to me since I'm predominantly a pre-NES gamer and I wasn't a fan of Genny at all in its day, but I've come to appreciate it much more since then. It's a great system.