Why not connecting it with the external memory bus?
I don't understand. What external memory bus? Care to elaborate?
@nootropic:
There is a via under one of your crystals (connected to GND I believe?). Just thought I'd mention it in case it was not intentional.
That's a very good point, you're right that it's something to be careful of. In this case it's OK because as you point out it's a GND connection, so it doesn't matter if it shorts against the crystal case. The plan with production of this PCB is to have all the vias "tented" (covered with soldermask) but even with tenting it's a good idea to not put vias where they could short out. A via under tenting is still a structural weak point for the soldermask and there's the danger of the connection being exposed.
In any case that particular part of the PCB is being shoved sideways a bit to make room to route those last few airwires!
Jon