While I normally don't care what I fly on, if I'd have to decide, I'd say Airbus... and here are my
reasons for that:
1. They look better (sorry for copying that line
2. Quieter interior (esp. A340)
3. Better comfort (wider seats on 3-3, 2-4-2 better than 2-5-2 or 3-3-3)
4. Better interior lighting systems (the normal light is not 'yellowish' as on Boeings, but much whiter - some don't like it, I do; and that dimming-system for longhauls is brilliant!
As for where the planes are built? I really couldn't care less - while I don't mind that they're built in Europe, I'd prefer them even if they were built somewhere else.
But, in general, I prefer the plane that gives me the better seat at a good price - if it says Airbus, Boeing, Embraer, McDD, Tupolev or anything else on the outside is, at best, secondary.