Are your tires old? I had a dry set of falkens that sounded like a worned out bearing, and almost took it in to fix... but when I got new set of tires (Vredestein) the sound disapeared...
And an alignment can't hurt... it can very well be an alignment problem...

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BMW X5 3.0si 2008
Premium Package
Light Package
Navigation
Reverse Camera
Rear Sensor (retro-fit)
Comfort Access
Spare Wheel
Power folding mirrors
Voice Control w Bluetooth
Power trunklid

BMW X3 3.0i 2006
M Aerokit
M Sport Package
Navigation System
BT Handsfree
Xenon HID

BMW X5 3.0i 2001 --- SOLD