My choices:
Burris, Leupold, T/C, Bushnell, Nikon, Sightron
I think that they are all excellent scopes, and have never had a problem with any of them. Whatever you decide to buy, don't go super cheap. I am a firm believer in the fact that you get what you pay for.
If I had to pick one of the scopes from my above list, I would go with the Leupold. That doesn't mean that there is anything wrong with the rest, they're just my favorite choice.