I use a Burris MTAC 1-4x with true or near 1x.
I attended a class with a Leupold VX 3 1.5-5.5x with circle dot reticle. The 1.5x slowed me down too much inside 20 yards. It makes you hunt around for a split second as the optic moves in line with your eye. I recommend you choose only optics that have true 1x or at most 1.1x. I also recommend that you get a reticle with a bullet drop compensator. It makes a huge difference in performance.
The 1-4x (or 6x or 8x) optic is the most versatile. The 4x ACOGs have all sorts of trouble inside 50 yards. Finding the target at speed and placing the rounds where you want them can be a challenge. The 1-4x eliminates this problem. I zero at 4x and keep the gun on 1x. If I need to take a long range shot, I have the capability and the time. The price point of the Burris MTAC (and similar offerings from them) is good.
I would definitely look at the SWFA SS HD 1-6x24 Tactical 30mm Riflescope. This is a good deal for the money, though other manufacturers have been releasing optics in a similar price range. You can get by with a Leupold VX/R Patrol with a 1.25-4x, but something at 1.0-1.1x is far nicer to shoot with from 5-300 yards.
Also look at the Pride-Fowler 1-4x. That reticle is exceptionally easy to use. I was able to score 28/30 hits on a steel plate at 600 yards on a gun I had never fired before.
http://rapidreticle.com/RRCQLR.php
http://swfa.com/Pride-Fowler-Rapid-Reticle-CQLR-Rifle-Scopes-C3298.aspx