I'm a rifle slut. I like to hunt with lots of different rifles. I've not killed near as many deer as a lot of folks here have, but from what I can remember right now as I type, have done so with the 7mm RM, 25-06, 6.5x55, .308 Win, 30-30, .338-06, .243 Win, and .257 Roberts. I have killed more with the Roberts than any other cartridge, and used it exclusively for over a decade, when the pace of work and deployments kept me from doing much rifle loonyism. Perhaps that makes it a favorite, but there are several more lined up waiting their turn in the decade or two I have left to take them afield. There's a .256 Newton, the .280 Rem I inherited from my dad (and several other of his rifles) a Griffin and Howe tribute 7x57 I'm building, a sweet custom 6.5 Grendel on an early CZ 527, and a custom 270 WSM with an 8" twist barrel. And on top of all that I recently bought what is my most accurate rifle ever, a CA Mesa 6.5 CM - a legit .5 MOA rife with both the 139 Scenar and the 143 ELD-X. By all rights it probably ought the be the only thing I hunt deer with...ever - but then there's that slutty character flaw I've described. But I have to say, that 1951 vintage .257 Roberts with the Leupold 4x has killed everything I ever pointed it at, and I sure do like it.
