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See what others say first, but I think the 4670 would be the better card.
http://www.techpowerup.com/reviews/Zotac/GeForce_GT_430/1.html
GT 240 seems like an overall best choice according to this review.
Got a GT 240 in my kids/other half's PC and although it's only been used to play World of Warcraft, it played it pretty well on medium settings @ 1920 x 1080 resolution. I originally chose this ahead of a 4670 as performance was meant to be similar to an 8800GT.
that link goes to a 430 review.