Legitimate answer time.
There is no one answer to this question, ever image requires a different approach. The best thing you can do is have you focal lengths covered. A good setup would be a wide zoom like a 17-50mm, a fast standard prime like a 50mm, and then a tele zoom like a 70-200 or 80-200. That will get you covered for most things. After that you could add something more specialized such as a fisheye, a macro, or another prime lens.
As for angles, the most important thing in action sports is context. By looking at your image, the viewer needs to be able to understand where the rider took off, what is happening in the air, and where the rider is going to land. We've all seen those news paper photos with a rider completely in the air, like is he just floating? Try and gauge the feature or line and figure out how you can best show what is happening while still being creative; if someone has already shot X trick from X angle, don't go there and shoot X trick from X angle, shoot DHDH trick from KJKL angle, haha.
Hope that helps,
Zack.