If we don't have to refuel, and we have pre-planned and pre-briefed a swift departure, from batteries on to taxy takes about 30 mins in a Global 7500 - providing it all booted up ok on the first go!
We usually allocate 60 mins for a "normal" pre-flight, which would allow for a mid-capacity refuel and loading some pax bags.
If we need full fuel, we usually pre-fuel (to almost full) the day before - it takes a long time to load 50,000lbs of fuel.