Automatic data collection could really help us with our lives in some areas. For instance, imagine if you were able to track automatically how much you were eating and how much you weigh, along with how much exercise you've been getting. It wouldn't get in the way of your daily life, because it's fully automatic somehow, but you can get all kinds of reports on how well you're doing at managing your incoming and outgoing calories. Or that other thing people want to know about themselves, where is all my money going? If every cent you spent was recorded and categorised, then you could get an idea at a glance where you're spending all your money, either by time of day, type of goods or services or even the companies to which your money goes.
Mokalus of Borg
PS - Personally, I'd like to see some biological measures like pulse, blood pressure etc.
PPS - But only if they could be collected unobtrusively.