Core i7 hasn't taken off with massive sales, but given its performance profile it won't be far off before a bigger portion of the enthusiast crowd choose to embrace it. But then there's the financial crisis against its success in this regard as well; something very few people have control of at the moment.
That said, CSX has done a very impressive job with its 2000MHz triple channel kit and is deserving of attention from those looking for top end modules. But while fast, this speed comes at a price premium. As you would expect, DDR3 still sells at a higher cost than the same sized DDR2 modules. And with three of them in the kit, it's going to cost a bit to get these high clocked modules into your rig, that is if you can even find them.