IMHO - I can't make a favorite airport out of the variables. Each has plusses and minuses w/ no clear winner...
Food: IAH SFO EWR ORD LAX IAD (LAX ahead of IAD because you can reach T6 via walkway)
To/from city: EWR/ORD/SFO/DEN/CLE
>> IAH/IAD/LAX (obviously I like airports that have trains)
Connection ease (just gate to gate, excl. IRROPS): LAX SFO IAH EWR/ORD/IAD
UC situation: LAX SFO ORD IAH DEN IAD
That being said, I would feel comfortable calling IAD my LEAST-FAVORITE hub.
Topic of "Favorite" and "Least Favorite" hub is perfect for a poll...