For airports I am departing from:
Car-to-lounge time and lounge-to-plane time is most important. This is why I like my home airport of BOS, as opposed to ones like ATL, etc.
For airports I am connecting in:
Plane-to-lounge-to-plane time is key, along with a good lounge. Airports like DFW, ATL and DEN score well in this regard, considering their size.
Which is why airports like MUC are so great. A large, easy to connect in terminal (term 2, for LH and *A) and four small, compact, modules in terminal 1 making departing in the other airlines easy and fast.