Walking gadget of choice

I like to know roughly how far I walk in a day. My first option is the mobile app, Runkeeper, which is accurate as it uses gps.
A must have gadget, amazingly enough is my Nintendo ds Walk with me pedometer, pictured. It records daily steps taken, downloads them on to the console and stores them. I get a fairly accurate reading when measured against the Runkeeper and it can be put in a trouser pocket and forgotten about until the end of day when records are checked.