The vast majority of my deer have been under 125 yards as well. This isn't Wyoming, and we don't have 400 yard shots around here. Yet I still see all kinds of hunters with 16 power scopes on their rifles (usually the guys who never actually come home with a deer).
A scope is an advantage. Deer are frequently low-light critters, most active dawn and dusk. regular iron sights simply disappear and are useless in that magical last twenty minutes of the day. A GOOD scope really helps in low light. I'd recommend something on the order of a 1-4x or a 1.5-6x. Keep it on low power, so you field of view is large for in close and rapid target acquisition. If that buck is feeding on the far side of the clearing, you have time to dial it in. A 1.5-6x scope often has a field of view that is about 60-70 fee wide at 100 yards. When your deer is only 20 yards away in heavy brush, your field of view is still a good 15 wide, and you can find him quickly. When you opt for some 4-12x scope, your FOV can drop to a measly 15 or 20 feet at 100 yards on low power. In close, your fov is so narrow, its hard to find the deer. You do not need high power for close range deer. FTIW, I currently have the following power scopes on deer rifles. 1-3x, fixed 2.5, 1.5-5x, 1/5-6x, 1.75-6x, 2x-7x. These work great on eastern whitetails.... My 'long range' rig (used on moose and caribou on lakes) is a 2.5-8x. Don't over scope your deer rifle.
A good scope is mandatory. Cheap scopes are 'dark', ad useless in low light. A good fully, multicoated scope has lenses that have every surface coated, and multi means more than one coating. These coatings increase light transmission. www.natchezss.com frequently has good sales on scopes. Leupold VX3 are good. Weaver Grandslam and superslam are Very good for the money.
I have not used one, but I expect that an aimpoint would be just fine for hunting deer to 150 yards. It will solve the disappearing iron sights issue in low light.