Also, I find that watching tv when I work out works great as motivation. There's a tv in the gym I use, and since I don't watch tv much otherwise it's kind of a reward at the end of the day to watch tv... plus, a lot of reality shows are focused on people losing weight or working out (Biggest Loser, Last 10 Pounds Bootcamp, Bulging Brides, etc...) which are ridiculous sometimes, but massively motivating. Jillian Michaels has never failed me yet
... also, for some sick reason, the Food Network entertains me during my workout time sometimes. I think it's something about seeing out of shape, unhealthy people eating ridiculously unhealthy food that keeps me on the treadmill. Kind of like inspiration by bad example.
Ooh- and any movies where people have to overcome some kind of obstacle and become insanely baddass. Never Back Down got me through so many workouts, I feel like I should send someone a thank-you letter.