Personally I´m most going crazy for awesome Innies like T-Innies or long and deep ones! :P
But I can also enjoy some very good and unique Outies, of course! Piercings, well, are on of the best inventions of mankind but surely are only meant for Innies
In percent I´d say:
50 % Innies
40 % Pierced Innies
10 % Outies