1.005-1.014 is a loose range of my personal preference. They can still taste good up to 1.025 (Lagunitas Sucks), but this is rare. I'd say try not to pass 1.017 for the most part. Don't rely on calculators to tell you what your FG will be. More often than not, the beer will attenuate several points lower than what is stated. But it does depend on many factors such as yeast health and selection, pitch rate, initial oxygenation, mash temp, mash ratio, mash time, grist make-up, etc.