I['ve] own[ed]... Red, Blue, Yellow, Gold, Colosseum, Ruby, Emerald (my favorite), Heart Gold, Soul Silver, Black and White. White is the only one I have currently, as many of my cartridges are lost somewhere at my parent's house.
What about you? Is leafeon your favorite pokemon? For me, it's Umbreon (but, believe me when I say- if Leafeon's shiney was autumn, it would definitely be my favorite).