Well I'll expand on what I said about object collision:
If you need polygon collision detail, use the object collision box, when you get a collision returned from that, switch on polygon collision, and then you can have that level of accuracy. After that, you switch polygon collision off again, and back to collision bounding boxes.
This way, only the two objects colliding will be switched to polygon collision, and your game won't suffer nearly as much in it's fps

I really think this only applies to games where you might want to say, have a fist collide with different parts of a body for instance, just don't look right if the fist stops in mid air and the target goes ouch!!
If you're just wooshing round shooting people, simple object collision bounding boxes are just fine, sometimes it helps to make them a little bit smaller than you'd think nessecary, depending on what angle you see your character from. that's all I'm using for my retro entry, 'cos I'm going for arcade speed in 3d, wanna keep the fps up
ZX Spectrum 48k Issue 3, Radio shack Tape drive, Rank arena 12" T.V. set.