Depends on the charger. If I'm at home, and I'm down to like 20%, I'm looking at 8 hours. If I got to a supercharger now, those things are fast. Hour or a bit more and I'm ready to go. The navigation system will actually tell you when it has enough power to get to the next supercharger on your route, but I often let it charge a bit more just to be safe.

Oh, and I should mention that Tesla recommends that you only charge your car up to 90% or so on a daily basis, something about how the battery discharges. With the new batteries, you're still looking at around 270 miles of range, which is plenty. I adjust this up to 100% for trips, but for daily purposes this cuts down a bit on the charing time.