Which graphics cards are recommended for Final Cut Pro X?

I'm in the process of downloading Final Cut Pro X and I'm truly exited.
I have a 2008 Mac Pro with 8GB of memory and am going to order 8GB more.
Now I'm looking to upgrade my graphics card. This card also should support Adobe After Effects.

Right now I have the NVIDA GeForce 8800 GT.
I wouldn't mind to drop some money. Maybe $800. I'm going to work in motion and hopefully with some RED footage soon.

The NVIDA GeForce 8800 GT has Open GL... But a friend just emailed me saying that the NVIDA GeForce 8800 GT is able to utilize OpenCL support "under Snow Leopard".

I'm wondering if my ATI Radeon HD 3870 will do the same?

Here's a list of incompatible graphics cards from Apple : [support.apple.com]

I have a genuine 3870 purchased direct from ATI when it was released. I was able to purchase, download, install and run final cut pro x, motion, and compressor from the Mac app store yesterday. It utilizes all 8 cores in my Mac pro from 2008 running the latest snow leopard. No workarounds, it just works.

I can confirm that the ATI Radeon HD 3870 graphics card in a Mac Pro 1, 1 works with Motion 5.