Find a rifle you really like chambered for any of those, or some others, and go for it. If you plan on shooting it a lot, maybe a .243, for all its virtues, might not be the best idea. A mid-range .25, 6.5, or 7mm might wear better.
I picked up a CZ 6.5 Grendel last year and it's a blast to shoot. Pretty light and handy, and light stuff is starting to look better to me these days. No recoil to speak of either. Plenty of power out to 300 or so for deer and such.
