Depends on how well, where you go to school, what field you want to go into, and when you take it.
There are generally 2 stratagies for step 2.
Option 1. Take it early. This is good if you are applying to a competitive (or not so competitive!) field and want to get your scores up. Benefits: opportunity to do better and get it out of the way early. Risks: you could do worse than on Step 1. Its a pain in the ass - why do today what you can do in a few months.
Option 2. Take it late. Like in the winter or spring. Benefits: All you have to do is pass. Cons: you have to deal with it later when you just want to be relaxing and taking cruiser rotations in the spring. A few programs want to see your scores. Risks: If you fail, this really screws up residency!!!
Option 3: Take it somewhere in the middle. If you do well, hope you took it early enough to get your scores to programs.
Talk to your advisor for info specific to you and how important your score is.
