I'll agree with the consensus that the 7mm-08 has high overlap with the rifles you already own. The 25-06 will offer some advantages in lighter bullets that the 270Win doesn't.
I don't think you'll have any trouble with taking deer with good shot placement. If you gut-shoot a deer, you're going to be looking for it regardless of what cartridge you're using. If you shoot the right bullets (not varmint bullets, but big game bullets) in the 25-06, you should be find as long as you don't shoot through the gut or some other terrible shot.
I will disagree with eford about the 25-06 v. the 243Win. I've got nothing but praise for the 243Win, on everything from the occasional small varmint, to coyote, to white-tails (and by extension, likely antelope and muleys). I watched my dad use his 243Win as his only centerfire rifle for about 30yrs, and he took deer in at least seven states and maybe more like 10 or 11. Never had a problem. When you move down to varmints, the 243Win offers a wider selection of bullets, lower recoil, and a cooler barrel due to less powder burned. Anything the 25-06 will take in the varmint world, the 243Win will do equally or better. But there's nothing wrong with the 25-06. If you're looking for something for yotes and deer, either one (25-06 or 243Win) is just about the best possible choice.