For many many objects, rectangles and circles work good. You can let every object have more than one bounding box/cirlce, too.

Ok, the good approach is, test bounding boxes and if they collide do the exact collision detection (if needed, meshcollisiontest).

The test with bounding boxes is very fast and it indicates which objects are "near" each other. Objects which don't collide by bounding boxes, cannot collide by mesh. So only test mesh collision when bounding box collision occured. (box-box, box-circle etc).

Depending on how exact your collision detection has to be (depends on the game), you could either do real mesh collision or give you objects more than one bounding box (a plane for example can have 2 bounding boxes building a cross).

Thats all I can do right now... I have to go back to my IGF entry... tomorrow is deadline and I am not finished yet

Greetings,
Dirk