Q: hey mike. I'm 23 years old 180 pounds with 18.5% body fat. Now my Q is what's a small but good amount a body fat to have?

A: There's no one answer to this since looks are so subjective. At 18.5% body fat you are probably close to average for men (if you are a woman then 18.5% body fat range is already quite low). If you are looking to have a well defined abdominal six-pack then you will need to drop to around 10% body fat. This would not be easy and may not happen at all, but you should almost certainly be able to drop to 12-14% range with a proper exercise and nutrition program -- you can start by reading How To Lose Fat and follow the directions given there. If you are interested, you could start your own Fitness Blog where I could monitor your progress and offer specific exercise and nutrition advice (for free, of course).