5D? - 1D - 1Ds

[Bevb]

Can someone help me to but the best camera for my needs!! I have decided to upgrade my 20D, i would like more pixels and the opportunity for full frame, but my photography is mainly wildlife and action so i need a good fps burst, the three models i am looking all miss one thing or the other, i have read reviews on all these cameras and obviously the 1Ds Mkll is the ultimate camera but the 5D is said to have a bigger buffer than the 20D (which offers 5fps) and the 3fps the 5D offers has been quite sufficient in tests and this camera is half the price. The 1D MkllN has 8fps but doesnt have a full frame (i think thats right about the full frame) i am just looking for advice and some guidance on this before i make a final decision.