I have a .243 and 7mm-08 among several other calibers. The 'tweener for me is my .260 Remington which has become my favorite big game caliber. Flatter shooting and milder recoil than the 7mm-08 and more umph than the .243 with similar recoil. All three are based off the .308 case so little or no problem finding/making brass. It's hard not to like any of the 6.5 calibers and most can be loaded with a wide range of bullets for varmints/predators to big game. And they're not lacking on the target range. So...of your listed calibers...I'd go 6.5 Creedmoor.
