Full disclosure: I am an engineer with 20+ years of quality experience, so I am very picky. This car is the perfect marriage of luxury and sports car. The build quality is very apparent, both inside and out. It is extremely quiet and smooth, although the suspension is a tad stiff on rougher roads. The paint is absolutely beautiful. Picking a color is the toughest decision, once you decide to buy. The engine will not impress true sports car enthusiasts, but I think Lexus hit the nail on the head by combining "very good" performance with "great" gas mileage. I'm getting 28 MPG consistently.
Keyless entry/start is not just a cool feature, very handy when your hands are full. Love the luxurious interior and leather seats. Exterior design gets a lot more looks than I ever dreamed. Great engineering decisions on power/gas mileage.
I also would like memory seats standard. It could be small for tall people (above 6'). I would add a better iPod interface.