I've always seen Nintendo as a non-debateable issue. You're going to get the console at some point, because its Nintendo. The other consoles/PC are the one you have to decide between.
I really don't understand why the Xbox is so popular here in the US. The only thing it has is FPS games... Is that really the only genre most American gamers are willing to play? That makes me really sad, because they will never truly get to understand games as what they are (and that goes for playing any single genre).
I guess its a bit of nationalism as well. The same way Asian (well mostly Japan anyway) folks wont buy a foreign (Microsoft) console, the Americans buy their national console as well, although to a lesser extent (there are still some PS/WII consoles sold in the US, whereas in Japan the X360 number is close to none)
I think the games come as the 2nd criteria and I guess US prefers shooting or just dont like the PS exclusives (duh! I like them)
I do share the same view as you though, I think the Sony console offers a better mixture of exclusives (now adding new IPs and Indie games into the mix as well)
Saying that, I owned the Xbox 360 first but then bought the PS3 the day it came out and never returned to the Xbox again (save for an occasional Kinect fun game)
With the next gen, I am getting the PS4 first and willl see if the XBONE offers any benefits later...