If you want a regular scope, most guys prefer scopes by Burris or Leupold. Especially if you shoot the heavy recoiling calibers, you'll want a scope that can withstand the recoil (and has a good warranty if it doesn't).
If you want a red dot, again the better scopes will last longer. I have a Tasco red dot on a 15" .44 mag barrel that does okay for hunting, but the dot is about 4 MOA. Okay for hunting, but not great if you are doing any long distance target shooting, such as for silhouette.