I have had some visual issues while playing halo reach. http://yfrog.us/4jkp9z I think it might have something to do with ny hdmi cables or some kind of interference, but I have yet to duplicate this for another game. (although it is kind of rare). Has anyone else had a problem like this?

Is your disk scratched? I know Microsoft has had issues with some Reach disks being scratched but I don't know if that would cause those weird lines to appear...

That is strange, I would think if it's a poor connection or some sort of hardware issue, disc excluded, then it would happen during any video playback via that connection. If you can't recreate this issue with any other game, then I would definitely say it's a disc issue and you might want to contact Microsoft.

Hyperlinked for ease for viewing.
 
I've not heard of any problem specifically like this myself but the fact it only happens for Reach suggests it's probably an issue with your disc.

I haven't seen anybody have a problem like this.  Most likely it is due to a bad disc.

I've seen lines just like that on computers a bunch before.  It usually means that the GPU is overheating.  This could be happening only with reach because reach is really pushing the system more than any other game thus-far would have.  I would heed atomastist's advice and keep it very cool.  I forsee an overheating error in the future

Okay, thanks for the help. I'll take steps to keep my system cooler.