RE: .270 or .25-06?
I'm a .270oholic, so it's tough not to tell you to use it every time. I think in your situation, I'd get the .25 because it's such a different caliber from the other two, rather than the .270 which is closer to the 7 mag. Also, like you said, then you could turn around and varmint hunt with it. The only problems I have with it are the .270 ammo's so danged cheap, and I'd prefer to have the .270 for mulies, though either will get the job done. Besides, if you move up to mulies and the .25's not doing the job, you can just dust off the 7 mag.