Which iMac video card best for HD playback?

[keboyle]

It's time for me to upgrade my iMac to a newer model. Depending on if I go new or refurbished, there are several video cards to consider.

I'm looking for a quiet card that can easily handle up to 1080p playback via Sage TV. My current iMac has an ATI 1600 and it is struggling to handle OTA live TV viewing. Game playing is not an issue for me. My most graphic intensive application is Photoshop and I am at best a casual user. Most of what I do is routine business tasks. I just want to be able to also watch live TV while I'm working without it getting pixelated and cranky on me. I'll need this machine to last my normal 3 year upgrade cycle.

Which of the following cards will handle live over the air HD playback easily and do I have them ranked accordingly? I want to narrow down which iMacs to consider and which to avoid based on the video cards.

NVIDIA GeForce 9400M with 256MB memory
ATI Radeon HD 2600 PRO with 256MB memory
NVIDIA GeForce GT 120 with 256MB memory
NVIDIA GeForce GT 130 with 512MB memory
NVIDIA GeForce 8800 GS with 512MB memory

In searching the web, I've seen references that the NVIDIA GeForce 8800 GS is good for gaming but not so much for media/video applications. Is this true?