I saw this article today on augmented reality. It doesn't use the phone — it uses Google Goggles, but you can imagine it as an application on a mobile phone.
The AR glasses makes the food products you see look bigger through the lenses so users eat less. [See article.] You can imagine more scenarios, though, with a mobile phone along with its processing power and contextual information about the user. If I walk in to a sandwich shop, for example, I can scan the options with my phone to find a sandwich that fits my calorie and nutritional requirements. (I spend a lot of time in airports so would love this). Certainly if I pick up a candy bar, I can read the nutritional information or calorie count.
I go back to trying to answer this question, "how does access to real-time information improve our lives — and not simply addict me to accessing information constantly like checking email or Facebook updates?" Health, wellness, and financial services among others are where I see some bigger opportunities.