There is no perfect deer caliber however a lot of good suggestions are on this page. My top five pics would be .243 Win, .270 Win, .30-30 Win, .308 Win, and .30-06 Springfield. Just for the simple fact that you walk into any store that sells ammunition you will find these cartridges on the shelf. 7mm Rem Mag is just as popular and as easy to find just a little more expensive most of the time.
I like these
.257 Roberts, 7-30 Waters, 7mm-08
as well as the .25-06, .250 Savage, 6.5x55, .260, and .280, but these are not nearly as common or as easily found. If you handload then it isn't such a big deal but it doesn't seem that the OP rolls his own. Don't overthink it and keep it simple when you look for your deer rifle.