Personally, I really dislike the "bling" look. I think it tends to cheapen and or focus unnecessary attention on the wheels, while losing track of the overall look of the car. That being said, my '01 CL600 came with the factory sport package and had chrome AMG monoblock style wheels. I took them off and went with AMG silver painted double spoke, 18", and think they look great. On a practicle matter, the lower profile tires will affect the ride of your car. I've damaged tires and wheels much more easily when going low profile/big wheels, etc.
Those are some of my favorite wheels, and I definitely agree with you about low-profile tires and oversize wheels. 18" is as big as I'd go on the 215.