One of the most controversial subjects in the field. I am personally a huge fan of the Paleo or caveman diet. Keep your diet high in GOOD fat, high in protein, and low in carbohydrates. I recommend caloric ranges around 40-50% fat, 35-40% protein, and <25% carbohydrate for my athletes. These are the ranges I personally use and have gotten pretty gnarly results. Increased energy, recovery, and decreased bodyfat. Can you ask for anything more?
To give you a quick summary on what you should eat: base your diet on vegetables, fruits, lean meats, fish, nuts and seeds, little starch, and no sugar. Avoid anything processed. If it doesn't grow from a tree, if you can't kill it to consume it, then don't eat it! That means say goodbye to your precious pasta, rice, and cereal. Dump it you'll feel better. Trust me. Robb Wolf has got sum very interesting stuff on nutrition www.robbwolf.com.

Check out my articles for a more in depth view on nutrition:

Paleo On-Ramp!

Nutrition for Performance vs. Aesthetics

Nutrition Guidelines