HD4870 1GB or GTX 269 Core 216 for gaming HTPC?

I was JUST (today) in the same situation and chose the GTX 260 core 216 as it seems to have better frame rates in the game I want to play right now (Mass Effect) compared to the 4870.

I chose to order this one http://www.newegg.com/Product/Prod [...] 6814127430 as it's was priced at $145 after rebate ($165 before rebate which is supposedly $10 cheaper than normal)
and it is also factory overclocked, and a supposed (I couldn't find it as the MSI site was down) 3 year warranty.
For me at the price it seemed like the better deal, but also it certainly matters what games you plan to play when you get it. For me it was obvious that it seems to favor the NVidia hardware over ATI for the price.

Also I have been told the GTX 260 is a bit long so make sure it will fit your case properly.

I would think the 4870 would be a good choice because of the HDMI sound output threw the card, but i believe the 260 runs cooler. you could have a problem with heat from a 4870 but if you get one with a non-reference heatsink it could be better. The 260 doesnt have audio on the card so you have to plug your TV in to the sound port if you want to use a TV, where as the ATI card has onboard audio that runs over a HDMI cord. Up to you on this on. The non-reference boards are more expensive.