best graphiocs card for animation

[Fighting HM]

I am building a high end computer for animation. Any ideas on what the best graphic cards for animation are?

This is what I have so far:

Asus A8N-SLI Deluxe nForce4 SLI
AMD 64 x2 4400
2 GB PC 3200 RAM
160GB SATA Seagate Baracuda
300GB SATA Seagate Barracuda
Sony DRU 810a DVD Burner
Koolance PC3-720sl Cooling Case
WIN XP Pro

Not looking fo total high end but somthing really good 400 dollar range.

Thanks...