I will follow along with some of the other good folk. I am partial to the 257AI as you can see from my handle. My other favorite cartridge is the 6.5x55 (Must be my norwegian heritage) They are both great calibers and will do equally well on deer. The 257 AI shoots a little flatter but the 6.5x55 will handle a little heavier bullet. Been shotting the 6.5 since 1974 and have both of my brother-in-laws shooting it now. My one brother-in-law figures that a box of ammo is worth about 10 deer and 5 coyotes. I keep him supplied with ammo and he lets me hunt on the place.

260 Rem.

Another 260 Rem vote

HogWild

For the purposes you mentioned, I believe I could find bliss in the arms of any of the following:

.250 AI (which I have and like)
.25-284
.260 Rem (which I have and like)
6.5-284

I would be wary of the .257 Roberts or 6.5x55 in a short action. Some say it works well, but I had a 6mm Remington on a 700 short action, and didn't like the way it fed. It actually feeds better as a .250 AI than it did in it's factory cartridge.

John