Been in, Mercedes McLaren SLR
Driven pretty much every Mercedes under the sun but a few that stand out are....
SL65
SL600 (R230)
SL55
CL65
CL600 (C215)
CL55
E55 (W211)
SLK55
Out of those my favorite is probably the SL65. There's nothing like driving Mercedes Benz twin-turbo V12 when you hit that sweet spot and you just feel 600 horsepower and 738 lb-ft of torque. Though I do wish the tires on the thing could handle the power. Traction control is always going off which is probably a good thing cuzz it keeps idiots like me from ending up in a light poll.
EDIT: Still waiting to drive the CLS55, that will soon be on the list I'm sure.