Polls deceive. I voted .243. But...My first centerfire rifle was an inherited Winchester Model 1886 lever action, .45-90. Never fired it, because everyone I asked said cartridges for that old gun weren't to be had (No one told me that I could have fired .45-70's in it!!!) My first 'experience' with centerfire was ONE shot with a Remington .270 and THREE shots with a Remington .30 (pump) when I was in high school. A pal borrowed his Dad's and Uncle's guns for us to try. By that time I'd had lots of .22 rimfire experience.
My first *extensive* experience with centerfire was with the .30 carbine in the service. The first rifle I bought myself, and took my first deer with, was a Marlin .35. And finally, the rifle I really learned to shoot with was a 6mm Rem. 700.
Polls deceive. I voted .243.