Probably my favorite caliber is .30.
I shot my first elk with a .30-40 Krag.
My first centerfire rifle was a .30-06 that I used for about 10 years for everything that I hunted in Colorado and Montana, from prairie dogs, deer, and antelope, to elk.
In the late '70s a friend gave me a .30 Gibbs case, and I thought that it looked so cool that I had my .30-06 rechambered to that cartridge. For the next 20+ years my .30 Gibbs put an elk into my freezer almost every year, plus 2 Shiras bull moose, an Alaskan caribou, and a mountain goat.
Then in 2009, after 40 years of wanting one, I bought a .300 Wby and after it's first hunt in Texas for exotics, I used it on a New Zealand hunt, multiple African hunts, a couple of Montana elk hunts, a Dagestan Tur in Azerbaijan, and for an Alberta bull moose a couple of years ago.