I would have to go with the OP...for just one rifle and 30 cal cartridge...
Marlin 336 in 30-30!
Used my grandfather's to take my first big game animal at 15...a whitetail doe.
Did use my Dad's '94 30-30 to take my first black bear, at 18.
Used my friend's Dad's BLR in 308 to take my first whitetail buck, at 21.
As a lefty, I have always loved the levers! Did not get my first left handed bolt action rifle until I was 30.
While I love the BLR (my 358 gets used a lot!) for the detachable magazine and ability to use spitzers...and a little more reach and energy...nostalgia will win out for the Marlin!
Of all the animals I have harvested over the past 35 years, the average distance has been 136 yards, so the 30-30 will work just fine, with proper bullet placement! (although it is not legal for bison in BC, and would not be my first choice for grizzly bear)
And I also have a custom LH Remington 700 in 300 WSM that is a great performing rifle, but again, nostalgia will win out for the Marlin!