2008 BMW 5 Series 535xi 4dr Wagon AWD (3.0L 6cyl Turbo 6M)
You won't believe you're driving a wagon. It drives just as well as the sedan. Sport seats are completely the way to go, very, very comfortable for long trips. Performance is great, next thing you know you're driving 80. Perhaps too many commands/too much functionality in iDrive, I would probably prefer a bit of a mix though in 2008 this got better - Audi MMI is probably better. But, that said, if you're familiar with computers, even at a basic level, you'll be just fine. Tight steering, decent suspension. Neat wagon-y features in the back too such as cubbys for groceries.
Engine. Road and steering feel. Car feels completely and perfectly balanced. Nice meaty steering wheel (sport package). Seats are incredible. Sunroof.
BMW already fixed it for 2009 - put buttons to quickly go to iDrive functions next to the wheel.