There's a wide variety of cartridges well suited for whitetail deer. Any of them TN said are excellent choices, as would be the 30-06 or the .270. Ammo for most of these would be (relatively) cheap and easy to find (25-06 and 7-08 might be a little harder than the others).
It would help to know where you plan on hunting and what sort of ranges you expect to be shooting. Also, you mention hunting other species, and for that, it really depends on what else you see yourself hunting. If your are talking about coyotes, stay toward the smaller end; elk & moose? stay larger (maybe larger than what's been mentioned here); black bear or hogs? somewhere in between.