ORIGINAL: zrexpilot
.22 Hornet
.222
.223
.22-250
.220 swift
.243
.240 weatherby
.257 weatherby
.257 hot tamale
or
any of the .300 mags
or .338 win mag
or .338 Lapua
All of these choices from a guy that only has a 22 Hornet!

And does well with it!

I would stay away from wildcats or not too common calibers personally.Go with a standard like 243,25-06,270 or 7mm class and there's plenty of choices and advice to help make it a good choice.