2008 BMW 5 Series 535xi 4dr Sedan AWD (3.0L 6cyl Turbo 6M)
I have driven this car hard for a year and a half and have yet to go through any technical problems with the car. This car is tough as nails. The engine is extremely smooth, and the Sport mode is like attaching rockets to your car when you need it to pass someone on the highway. The trunk is spacious, as is the rear seat, as two 6'2 guys have sat comfortably. The N54 engine (the TT L6) is easily one of the best BMW engines, and has won Engine of the Year awards consistently. Has never been to the shop other than scheduled maintenance, despite being somewhat abused by a young driver with a lead foot for about 14,000 miles. Never had a problem starting in cold weather, and no malfunctions.
Quick enough to dust most cars and safely overtake others, yet still tame for someone that doesn't drive "spiritedly" often. For those that want more power, inexpensive tunes are available to easily get 380+whp. Does void warranty, though, a risk one will have to consider.
The high-pressure fuel pump is still an issue with any BMW model with the N54 engine (135, 335, 535, and the x5/6 with the 3.0l engine) but mine has yet to go out.