The Flip Belt (get your HERE) is a great new design to the old fanny pack, to carry your phone, keys, money, and ID. You can wear it at the gym or while out for a run. All your things stay put, and by just flipping it over, they are all secure as well.
Heart Rate Monitor (Click HERE to get yours) I personallty have the Polar FT7, and LOVE it. However you can get whichever best fits your budget. It is critical to know what your heart rate is at while working out and you can only get a true feel for your Calories burned by wearing one while you workout.
FitBit (Get yours HERE) Tracks steps, distance, calories burned, stairs climbed, active minutes, and sleep patterns. Can be worn just about anywhere on your body, and will help keep you moving. It's a great way to make sure you get the minim 10,000 steps required in a day.