My go to rifle is a Smith and Wesson 7mm Rem Mag. I have worked up a handload that I have fell in love with and I can't help but pull it out of the cabinet since I know the ballistics chart better than my kids birth dates. I even know what temp and elevation will do because I have shot the rifle in so many times in so many conditions. I've also done some custom work to the rifle such as glass, trigger work, and my favorite scope sits on top of it. The rifle was the first I ever purchased while I was in college so I have just been shooting it for so many years.
I now own several rifles and I have many others that are more than capable including a few in the .30 caliber range but I just can't get away from the 7mm.