Wouldn't it be the one that's killed the most deer? The 30-30 of course.
Man there are sooooooooo many good choices out there for deer. I currently use a .30-06 beause it's my all around rifle and works well. I like the 30-06 and it's varients a lot like the .25-06, .270, .280. I also think the .308 and it's brother the 7mm-08 rate just as well.
S&W 5906 9mm, FN commercial Mauser .270 win, Winchester 94 .30-30, Ruger Redhawk .44 mag, Ruger 10/22 .22lr, Ruger P-95 9mm, Savage 110 .30-06, Norinco SKS 7.62x39mm
I support our constitutional right to arm bears.