Graphic designer Nicholas Felton keeps track of how many miles he walks each day. He also records how many book pages he reads, how many work e-mails he sends, and what songs he listens to. Felton's become somewhat famous for his obsessive self-tracking, and the slick info-graphics he produces on himself each year. Both the Wall Street Journal and Slate have made videos about him, here and here.
Felton began tracking his daily habits and compiling a Personal Annual Report in 2005, available at his website.