You are asking a tough question, and only you can provide the best answer for yourself. I have shot deer with 30-30, 30-06, and 243.
I would stay away from the neck shot, unless that is your only choice and you have a good tree to lean against. Not that what the others are saying is wrong. There is no doubt, it will down a deer fast. But it is a tough shot to make. I personally like that front shoulder.
If the woods you are hunting in is very thick with cover, I would go with the 30-30. If it is somehwat open, and you are using a scope so you can pick your shot between the brush, I would go with the 243. If you use the 243, use the 100 gr bullet.
Finally, which gun do you shoot the best with? What ever it is, the 30-30 or the 243, that is the one I would use.