Personally I don't think you would go wrong with a 7mmRemMag or a 300WinMag. I debated this myself not long ago but I ended up choosing to have a 300WinMag built.
I personally like my 6.5x284. As for barrel life I dont think its hard on barrels but from what I understand it is hard on the throat. Im sure someone on here can verify that or not. I try to give my barrels pleanty of cool down time between shots, I also like to keep it clean. I have roughly...