Ok I'll suggest something no one else has... the new '09 CTS-V. When it comes out of course. I have an 04 and it never disappoints.
http://www.edmunds.com/insideline/do/News/articleId=121130
7.0L LS7 engine, 505hp, 470lb-ft. I'm in love with the new CTS as it is and I'm going to test drive the V the minute it gets off the trailer at the dealership.
I don't understand the Mercedes fascination? They are sharp looking cars and are powerhouses but they are, in my opinion, not the definition of German engineering anymore since they have more problems than probably all of Fords' brands combined. If you get a Benz make sure it has a nice big fat warranty.
Edit: I will give you the fact that the AMG's are better built since they are hand assembled by a select team. But they do still have the nightmarish transmissions that plague most Mercedes