The biggest men's pant length issue is the pant being too long. The visual streamline is broken with the bunching of the pants at the ankle, which makes a man look shorter. Aaron Marino of alpha m. also discusses pants being too short and shows a prime example.
You don't have to be a fashion or style expert to see that the pants are too short. He needs an in between size. So, purchase the in between size and take them to the tailor. All pants should have a slight break in the front (see Aaron's example). Anything more than a full break, and the pants are too long. Aaron prefers to look at the heel. The pant should barely touch at the top of the heel. You don't' want your pants dragging on the ground. With jeans, you have a little more leeway. Make sure your pants are the proper length so you are always looking your best.