Depends on what you want to hunt. If it' s just whitetail then a reasonably powerful rifle such as a .270 or 30.06. Personally I' d only get a shotgun for deer if I hunted land where using rifle was a safety problem.

If you want to hunt birds too then a 12 gauge with both slug & regular barrels might be worth a look. Or if you want to shoot varmints maybe a .243?

Also check the MS regs to see if they allow muzzleloader in the regular rifle seasons. Buying one of those would get you more time in the woods.