Perfect Varmint Caliber???

[Big joe]

I already have a 243 Win., 270 Win. and a 300 Win.... I'm now thinking about a varmint-only caliber. I'm leaning toward the .223 Rem. right now, but before I make a big decision like this I'd like you guys to give me your opinion. If you were to buy a caliber for plinking, target, fun and varmints only ... what would it be and why ???

Thanks