Getting exercise started is the hardest part for me but I found that getting up early and going for a 1 mile quickly paced walk before work every day has actually given me more energy than the days when I slept until the last possible minute and rushed to work. My energy lasts throughout the whole day. I don't need energy drinks, extra vitamins, or that 5 hour energy stuff you see on tv. I never thought I could wake up early since I've never been a morning person but I love it now!
I use Dr. Scholls walking shoes ($50 at Sears) and they make that mile a little more difficult but I can feel the burn in my calves a lot more so I know they are getting stronger. You can also add ankle weights if you don't want to get special shoes.