I agree with Stubbie too, the 6.5X55 is a good caliber! I am going out on a limb here, but by your questions, I'd say you don't have too much experience with rifles!If thats right, I'd caution you not to go with too big of a caliber without knowing what kind of recoil that you can tolerate!
6.5 should really fit the lower recoil bill too!