I kinda like the bullet to dump as much energy as possible into the deer. Bigger exit wound that way, which leads to a better blood trail . . . I've used both Winchester Fail Safes and Winchester Ballistic Silvertips on deer. I prefer the Ballistic Silvertips; yet the Fail Safes aren't slouches, either.

Having said all that, the optimum bullet is one that you can put in the vitals on a consistent basis. In other words, the one that shoots the best out of your particular rifle.