I love stats. I´d take the risk to assume everyone loves stats about his favorite games. It´s the reason why playing Super Smash Bros. Melee was so much fun (well, part of the fun). Stats give you insight into your individual playing style. The data often shows habits or simply what actions you prefer. And despite all that additional, passive fun, stats are still something rare in video games.
There really isn´t much more to say. Get stats into every game where it makes even slightly sense. No wait, put it into every game, no matter of how much sense that makes. I want stats in the next Zelda-game, showing me how many enemies I killed, how I killed them and how many meters I ran in complete. I want to know the jumping distance in Super Mario Galaxy 2 and how long the longest time in mid-air was. I want stats in Mass Effect 3, showing me who I had the most romances with, who I talked most with and how my moral developed over the course of the game. Give me also stats in the next Mario Kart-game, which actually would make sense. Give me stats about any activity I could possible engage in on my consoles. And then, at the end of all that, let me compare my various stats with those of friends.
Stats, especially when you can compare them with others, are great fun for those interested. And I fathom that it´s rather easy to track the data for these stats in most games. Seriously, give me stats for every game out there. Let the consumer decide if he wants to look at or ignore them. Stats are fun.