While the question was incomplete, not impressed with many of the answers
Questions best to give a genuine answer speaking as Deer Hunter for 46 years is
Where are you hunting, and is the deer whitetail or Mule Deer
What is the terrain and cover; open range, farmers fields with wind breaks, plains, heavy bush or a combination
.30cal rifles such as 30-06 (my all around), .308, 30-30, 303 Brit, 300 Savage will generally do it all.
For open country 150gr pointed soft point or ballistic tip is good from 50 to say 200 yards plus
Here in say Eastern Ontario farm country (say an average shot 50 -100yards + or central Ontario up at 1000 to 1400 ft 1940s 1950s logging country open areas, heavy brush, lots of twigs and branches to foul your shot then a 180 gr round nose projectile as a "brush buster" slower moving, less prone to deflection but will shot and kill up to 200-300 yards
Next part of the question is what can you spend?
Optics; a good wide field of view duplex crosshair in a 1.5 to 4 power or 5. Get a 3x9 and you are going to lose field of view for fast explosive while shots, and man do the move and bound, explosively . At low power mine has about a 75 ft field of view at 100 yards (very good!)
Hope that gets you off on the right foot. Choice of action from bolt gun, lever action, pump, semi auto is a personal choice