Time and time again I've stressed to you all how great keeping a food diary is for watching (and tracking) what you eat on a day to day basis. So why not keep an exercise journal too?
The BodyMinder Workout & Exercise Journal ($10.17) is a compact and portable notebook/diary for keeping track of all your exercise experiences. I love it because it is organized and convenient (both of which are not always words I associate with working out). Plus, in addition to workout details and other exercises, it has room for daily dietary notes and other related items. The journal does a great job of helping keep track of the weights used and reps performed, so you can go back to an old routine and see what you did as well as the intensity you did it at. Buy the journal from Amazon.com.