I'd pick the .308 over the .243 if you are going to be taking longer shots.
All the calibers that use the .308 case are good deer getters!
.243, .260, 7MM-08 and the .308! You really can't go wrong with any of them for deer! The .260 and 7MM-08 give you great .308 preformance with flat trajectory too! Give 'em a look!