I saw some rather convincing data on the subject. I figured others would have other opinions based on observation rather than data that are equally relevant. These are the sports in which the a team gains the greatest advantage by playing at home. My list from weakest to strongest:
6. NHL
5. Soccer1
4. MLB
3. NFL
2. NBA
1. Going home at lunch to take a dump.2
1This one is tougher because of variety of leagues and the disparity of wealth between teams within a single league
2 Now thats what I call home field advantage!