Right now I think that the upcoming SL 65 AMG is the better deal compared to the SLR.
Honestly, I don't like the SLR too much. The sidepipes look strange and the very "feminine" body isn't quite my taste.
Right now I'm waiting for the engine figures to be able to create my final opinion.

Imagine this: a SL 65 AMG with 612 HP, any Tuner can get at least 700 HP out of this superb engine.
Now imagine a limited slip differential and the fun begins.
I know, the SLR is much lighter but I don't think this car is much faster than a SL 65 AMG on the Autobahn. And honestly: does anybody think that SLR owners will drive their expensive toy on the track? I doubt it.