Has anyone made the perfect health gadget yet?

I'm still undecided which health gadget to get, and you know that with Christmas (food) and New Year's (as in "resolution to get healthy") around the corner, the choices are only getting harder. A year ago, I would have just thought that Fitbit was the answer. Low profile and detailed metrics is definitely the key to putting the thing on, but now that there are so many different products that have different features, it seems like an over saturated market, yet no single product has that magic X-Factor that convinces me to drop $100+ on it.

I mostly know people (from podcasts) that have Fitbit, but it seems to be lacking any sort of social integration. They'll say that their motivation is trash talking each other about how many calories they've burned and compete, but it doesn't seem addictive enough to keep people hooked. When you think about it, we've already created a phenomenon where people quantify their "achievements" and are able to compare with each other... video games. The XBOX gamerscore immediately took off as a way to boast your achievements to friends and compete. Does any health gadget emulate that concept? BodyMedia's Armbad does have more room for that, and I talked to one of their reps at the Chicago gdgt live event, but he was like, "Sure, we have an API and someone can go make that if they want." It doesn't really seem like any company making these devices intends to tap the "achievement hunter" audience. Having a website and mobile app is great to view your own metrics, but I want the pressure of competition to motivate me - and let's face it, shame is a great motivator, which is why there's a market for the Withings Body Scale that tweets out your weight. Whether it's a couple's way to bond or your Twitter followers telling you, "hey fat ass, I noticed you gained weight last week," there's a strong desire for other people to make us exercise.

Anyone feeling the same way? Any devs out there trying to create this functionality? Would anyone accept an internet/public challenge to see how many of your friends can do the most ? We have a whole new culture of people who are addicted to living social and publicness (see: Jeff Jarvis) that could only be a successful way to get people healthier.