It really depends on the specifics of the beer for me (is it a big beer, does it need dry hopped, etc.), but in general since I've been kegging (last October), I've split my beers into 3 categories:
Short
Medium
Long
Short beers are generally low ABV and require no dry-hopping. For those I am grain to keg in 9 days:
Ferment at low end of yeast tolerance for 5 days. Then ramp temp to high end of yeast tolerance for 2 days. Then cold crash (fining with gelatin if you want) for 2 days prior to kegging. I then do the carb at 30 PSI for 36 hours and reset to serving pressure method, so I can be trying it at about day 11.
Medium beers are generally low/mid ABV and require dry hopping. For those I am grain to keg in 14 days:
Ferment at low end of yeast tolerance for 5 days. Then ramp temp to high end of yeast tolerance for 2 days. Then set temp to 65F and dry hop for 5 days (I use about 20% more hops here than the usual 7 day dry hop method). Then cold crash (fining with gelatin if you want) for 2 days prior to kegging. I then do the carb at 30 PSI for 36 hours and reset to serving pressure method, so I can be trying it at about day 16.
Long beers are generally higher in ABV, require dry hopping, and/or have significant amount of kettle hops. For those I am grain to keg in 21 days.
Ferment at desired temp for 14 days. Then set temp to 65F and dry hop for 5 days (I use about 20% more hops here than the usual 7 day dry hop method). Then cold crash (fining with gelatin if you want) for 2 days prior to kegging. I then do the carb at 30 PSI for 36 hours and reset to serving pressure method, so I can be trying it at about day 23.
Please note though, that while I can usually be sampling a beer at 11, 16, or 23 days, in almost every circumstance I've found that the beer tastes better (less "green") after it's spent an additional 3-4 days at serving pressure in the keg.