Been using Whirlpool forever, so we just stick with that. Though GE should be pretty good too as many people have them. I would just make sure that you read the reviews because sometimes they have really good or bad models for each brand. It really comes down to GE or Whirlpool if we need to get something.
As mentioned above, I'd stay away from Samsung or LG. They seem more expensive up front, and to repair (if necessary). Their reliability is also questionable.