Graphics card for video editing

I am trying to get a config for video editing mainly. I chose all components except for the graphics card which I hesitate between several models.

- ASUS ENGTX260/HTDP/896M - 896 MB TV-Out/Dual DVI - PCI Express (NVIDIA GeForce GTX 260 with CUDA)

OR

- Sapphire VAPOR-X HD 4870 - 1 GB HDMI/DVI - PCI Express (ATI Radeon HD 4870)

This may be unnecessary to use what I will do (video, computer graphics)

- Sapphire VAPOR-X HD 4870 - 2 GB HDMI/DVI - PCI Express (ATI Radeon HD 4870)

- ASUS ENGTX280/HTDP/1G - 1 GB TV-Out/Dual DVI - PCI Express (NVIDIA GeForce GTX 280) - 3 year warranty

What do you think? I'm more tempted by the Vapor-X HD 4870 - 1 GB

if you do not play, have a HD4350/HD4550

For the rest of the parts, I'll get:

Motherboard: ASUS P6T (Intel X58 Express) - ATX - 3 year warranty

Processor: Intel Core i7 920 - Socket 1366 Quad Core 4.8 GT QPI/s 8 MB L3 Cache 0045 m (boxed version - 3 year Intel warranty)

Memory: Corsair XMS3 Triple Channel 6GB (3x 2 GB kit) DDR3-SDRAM PC12800 CL9 - TR3X6G1600C9 (10 year warranty Corsair)

A HD4350 or HD4550 sealing the config just right?

you plan to make 100% of video editing and 0% of games?

no, let's say 85% of video, infographic; and 15% of games in full.

In accounts you play what kind of game? and what resolution?

For games I can not tell you. I'm not playing right now but I want to be able to play new games, if one day there is a good bunch to me.

For now I keep my 17" with the resolution 1280 x 1024, which does not require much resource, but since the ATI 4870 offers an HDMI output, I think in the coming months I will take a HD screen (for video and AC will be a good point!)