Spend the money and get the rear view camera, if not even the corner cameras. The car is higher and wider than the 5 series and I've already turned to tight in/out a driveway curb and ended up jumping the curve. You won't do it again, once you've done it once or twice from not paying attention, but it scares the heck out of you when you do it.
The regular sound system is good enough if your older than 40, and I installed the DVD inmotion software, so I don't miss the rear seat entertainment system. If I had money to burn (more money, that is) I would have gotten the comfort entry package that unlocks the doors from just touching the door handle or has the power trunk open and close, but that's just wanting to be lazy! Definitely think about the cameras though!!
550i GT Black Sapphire Metallic w/ Ivory White and Black Nappa Leather, Cold Weather Package, Sport Package, Black Foose Legend Staggered 20s, DVDinMotion software, H&R Lowering Springs, Black Kidney Grill swap, and the Dinan Stage 2 Performance Software: 501 HP @ 5000 RPM / 580 FT-LBS @ 3500 RPM (w/ Cobra iRadar)