Your subway route to Grand Central from Brooklyn Heights

Taking into account pleasure of ride, time on train, crowdedness, and cleanliness, whats your favorite subway line to Grand Central from the Heights (assuming that the 7 or S during the week runs frequently enough). Obvioulsy the 4/5 has the fewest stops, but can be so packed and hold for eternities between stations. And if you're more north Heights, do you take the A/C or 2/3 to Fulton and transfer to the 4/5, or shoot all the way up to 42nd and 7 or S it over.

Me, in the north heights, I'm thinking 2/3 to 7 in the morning and 4/5 to Fulton and A/C to High with crappy weather and Borough Hall or a walk over the BB from BB/City Hall when the weather is pleasant and I want the exercise.