I've thought for many years that a 6.5X55 is the perfect deer cartridge if a man hunted only deer: One rifle for all of the deer in North America, from little island blacktails and Coues to massive Canadian mule deer, from thickets to wide open spaces. The 129 grain Hornady would be a sweet match.
7mm08 is probably a more practical generic ideal.
However, in my heart of hearts, especially since I like to hunt mule deer, I'd make my perfect deer rifle a .280.
