For years, I used a Remi 270 BDL, and still think that the 270 is the "best" whitetail round overall. The 6mm or 243 is about as light as you want to go, I think. I think the 300 is about as big as you want to ever go. A lot of people used to shoot 30-06, but its not as popular as it was. I currently shoot a 7mm-08, kind of a hybrid round. Google it up, the stats on it are real good and it doesn't knock your arm off. I also have a 308 and it is my most accurate rifle, but it has a fluted, hex barrel and a big scope and the sucker is heavy. So, I don't carry it as much, but 308 is very good. Caliber of choice for snipers, back in the day. Also have a 264 mag, old caliber, expensive shells, but it is an excellent rifle. A few of my friends shoot 257, also an older caliber making a bit of a comeback. Stats are good on it. 7mm or 280 (about the same round) are still very popular, fast with a lot of energy. If you want to go big, I'd compare the 7mm to the 300 before you picked. Another lighter rifle to think about is the 25-06. I had a Sako model and it drove nails. My brother borrowed it and....yeah, I miss that rifle. But finally here is the thing: if had to just keep one deer rifle and give the rest away, I'd keep my 270 Remi for the simple reason that I have the most confidence with it in my hands. The others are perfectly good rifles, but that one is old faithful and has never failed me. And honestly, all things considered, I'd rather have a $400 Ruger with a $1000 Zeiss or Swarvoski scope, than a $1000 rifle with a $100 Bushnell. So, figure that in as well.