I have and do love lots of different rounds in lots of different weapons, BUT, I really do love the .30 cal. The 30-06 Model 700 Rem that I presently (and for years) have absolute confidence in has been dead-on with every gr. round fed to it from 125 gr. Speers and Noslers up to the max. of 240 gr. Sierra HPBT. The only limitation with these different handloads is the game one's after and the shooter's ability. This particular rifle especially loves .165 gr. rounds and for 90% of my shooting is what it shoots.
However a .300 whisper that can shoot with extreme accuracy from either my handgun or my son's rifle and can also be loaded with anything from 240 gr. subsonics to 125 gr fireballs is also fantastic. You just have to open up .221 Fireball brass to accept the .30 cal. bullet (which is longer than the brass).
But to have even more accurate, long range fun---I also love the .309 JDJ. .444 Marlin brass necked down to accept the .30 cal is nothing but fun ,and deadly.
This is probably more information than anyone wants, but I'm not on here often as I'd like and wanted to spit it out while I could.