Please forgive my ignorance of such matters - this will be my first bottle cage since camelbaks were invented.

Any suggestions for a secure, bombproof cage? it'll be mounted on the bottom of the downtube of an AM bike and needs to handle fast rocky descents and small drops. I imagine I could get some sort of rubbery strap to cinch it but I'd rather have a cage that doesn't need augmentation if such a thing exists. Bonus points awarded if it comes in purple ano but I'm not picky.