Just saw that this post got pulled out of the other thread and made into it's own thread, so I just cut and pasted my response from there:
As for the one rifle question, realistically it is erroneous as it will probably never actually apply to anyone interested enough in guns to read it here, much less post an answer.
That said, humoring the concept for a minute, if you are looking for one rifle for targets, prairie dogs, coyotes, antelope, hogs, deer and elk, I think the Creedmoor would be a pretty reasonable choice, especially since most folks are going to shoot much more of the first six than the last. If you just want a single rifle for hunting mostly elk with some deer, minimal varmints or targets, the .30-06 would probably edge the 6.5 out for me.