I think it's hard to beat the design of the new terminal B/C at
Ronald Reagan Washington National Airport KDCA.
The architect was Cesar Pelli. Not only does it look nice, but it
works. The very narrow space means that the main building is long and thin, but the side toward the field is mainly glass. The fingers with the gates are reasonably short and terminate is glass waiting rooms. Most of the eating places are at the gates, beyond security, but the three more upscale eateries are along the main Concourse where there are a number of shops. The Metro station is reached by short bridges with moving walkways (that sometimes work). The parking garages are just beyond that on the same enclosed walkways. The garages are unusual in that the upper levels are each slichtly inset with flowering bushes in the exposed parts. Nicest-look multilevel car parks I've seen. One can ride one's bike from downtown DC without crossing any streets.
http://www.mwaa.com/_/Gallery%20Imag..._aerial_bc.jpg
Terminal Map
Checkin counters are on the balcony.
http://tinyurl.com/8uyr3b
The new Southwest Airlines terminal at KBWI is also nice and spacious, but more conventional. I can't find any useful pictures.