I think the best beginner deer gun would be a 243 or a 25.06 or a 270 or maybe a 280, but you might like a 30.06 but maybe just a 30.30. No now thatI think about it you should get a 308! But you might want to grow with the gun so you should get a magnum, probably a 300 RUM?

Seriously, there are a lot of great choices out there, but we need more info to help you out. Just from what you asked, my answer would be a 270. Good Luck!