What's your favorite hunting rifle caliber?

[radar ralf]

I am partial to the .30-06 Springfield, but I am thinking of purchasing a new rifle, and I am trying to decide between the .300 Remington Ultra and maybe a .416 Rigby. I own several hunting rifles in various .30 calibers and some bigger calibers, but nothing above the .375 H&H. To be realistic, I'll probably never hunt outside the Americas, so I probably don't need anything bigger.

Maybe something smaller, like a varmint rifle. Does anyone have any experience with the NEF / H&R rifle? Maybe a heavy barrel .223 would be the way to go. I wonder how awkward this single-shot rifle is to reload?

Hopefully some of you folks can give me some good feedback on hunting rifles.