I'm very torn when it comes to this. I love games of all types. When I first started hearing about the "gamification" of everything it was touted as Web 3.0. It clearly has a lot of people excited. Maybe it's just because I trend towards indie games these days; games made by people who view them as systemic communication, trying to make meaningful experiences. But I guess I'm just elitist and view all of this as kitch.
I started to type a long rant about Farmville, but it's not worth it. My point is that I don't think this is going to last with its current trajectory. Gamification is a creative solution to many problems, but it often isn't being implemented by creative people. They usually just copy what happens to be working at the moment. I think eventually things like achievements are just going to become noise to most people. For this to extend to the long term we need more people who really understand the various ways play creates productivity whom can start experimenting with the next big thing.