That's a personal decision. You'd likely be happy either way, but you'll likely be choosing between:
1) higher resolution, with sharper image, but you might have to lower a few settings.
2) lower resolution, with grainier or smaller image, but you'll be able to get closer to max settings (you still may need to reduce settings here and there).
That choice will always exist when looking at 2 different resolutions. Higher resolution is a setting of its own. The question you have to ask is if the higher resolution setting is worth more than having higher of the graphical settings. Both improve image quality.