Simmons Prohunter 2-6x is a good budget friendly model, and has done well for me on my 44mag SBH with 300grn loads for a long time.
The Bushnell Elite 2-6x is a bit cleaner around the edges than the Simmons, and a bit brighter with a bit better resolution, and twice as expensive.
The Leupold VX3 2-6x is the best of the best, but costs about 4x the Simmons, twice the Bushnell. I only have one of the FX2 Leup 4x's but it's a great model.
The disadvantage of the fixed 4x power Leup FXII scope is that it's just at the upper end of what most guys can tolerate without a rest. The crosshairs get twitchy, and it makes guys think they're bobbling all over the place. It's nice having the variable power to get down to 2x when shooting off hand, but still have the option to crank it up when supported.
Depending how far you'll plan to be shooting, you might also consider an open style red dot sight like the Burris FastFire III.