Personally, I have and love the .270 for Texas critters. If you think you might want to go to larger animals (big muleys, Elk) in the future and want to keep the same gun, consider a 30-06 instead. If you handload, or know someone who does, you can get identical balistics out of either cartridge with modern projectiles and poweders.
Remington 700, or Winchester M-70's are both top of the line (production) models and the differences are insignificant. If you're looking on the used market, the old-school versions of the Ruger M77 are wonderful guns, and can often be had reasonably...they're a great combination of the Remington and Winchester's features.
You do understand that "Best Caliber" or "Best Rifle" is both a multiple beverage discussion, and has started many arguments? I've been involved in one such discussion for over 20 years! LOL