My favorite is 308 with 150 grain flat base interlocks.

The buck I shot this year was with a 223 with handloaded 65 grain Sierra Gamekings. I used it because I had just bought the rifle and had too many people telling me that I'd lose deer if I shot it with a 223. The handloads were actually made for an AR I had. I didnt have enough time to work up a load with anything else. I just grabbed a handful and shot a 1" group and went hunting.