If the CZ-550 is your choice, for sentimental reasons (European rifle needs a European caliber), I'd also recommend the 6.5x55. For practicality, .308. But that is dependent on how much plinking you want to do and what type of game your future hunting will include.
If you shoot alot and plan on keeping your hunting to New England whitetails, either the 6.5 or 308 will work.
I am also recoil shy (read wuss if you like), the 30-06 or the 9.3x62 will recoil more, but all bets are off if you plan to handload. 30-06 can be brought down to a 308 level and with Barnes bullets available down to 110 grains, it can be very mild. Add to that, the little extra weight of a longer action, it may be a little more versatile.
The 9.3x62 also can be loaded down but does not have the bullet selection of a 30 caliber. It does have the coolness factor of being legal for dangerous game in a couple of African countries.
In the end, it is all up to you. If you plan to shoot lots, then get into reloading and pick your favorite (mine would be the 6.5x55 from your list). Bullet ranges I've found are 87 grains to 160 grains.
Good luck in your choice.
