Preferred open world game.
Have you played The Elder Scrolls: Skyrim?
Borderlands, Far Cry and Batman:Arkham series games are a blend of linear and open world and imo they're all a blast to play. Also Fallout-3 and Fallout: New Vegas but I'm not up to date on the latest trainer status.
Here's a recent post of some of the CH members favorite games. Not all Open World but there's a lot of great games listed and something might interest you:
[Edited by element5, 4/8/2015 8:37:50 PM]
More like Old School RPG's. Like BG.
Really fun, IMO.
And, CH has a great Trainer/Editor for this game.
* Updated game trainers and cheats daily
* Get notified when new cheats are added
* Request which games get new trainers
* Priority support with any problem