I would rather buy the SL65 AMG. I think the SL65 is beter value for money, and it has a engine that blows everything into the woods, including the SLR.
If I can pick one to take home, it is a no brainer. I'll take the SLR. Although it doesn't have as much power(torque) as the SL65 AMG, that which it has is used much more effectively. It is also much more beautiful than the SL.