I'm not sure that I 100% understand the point of this thread. If your looking for a versitile, do all cartridge whilst excluding the ones on the list, I would have to choose the .270 winchester. If your looking for a good, split the difference caliber to fill the hole between .223 and .30-06, take the 7.62X39.
If you are looking for a versitile, do it all cartridge, why exclude the .30-06? And if you already have one, why bother getting another cartridge to do the same job?