The Asus 660ti or the AMD 7950 would both be good choices. They are pretty much tit for tat. The 7950 is cheaper after rebate tho. Not sure if the extra RAM is really needed gaming @ 1080p, but it is good to have.
Does he like Batman, btw? Comes free with a 660ti purchase...so while it is $20 more overall it breaks even when the game price is included.
If he is a noise nazi like myself, which ever card has better load temps so the fan can spin the lowest is the one I'd go with because gaming wise you won't notice any difference.