If you plan on running gt430's in SLI, just get a GTX 460 for $130 (recertified EVGA).
I was gonna get a Radeon 5770 until I found this deal. I ordered all my parts last night.http://www.newegg.com/Product/Product.aspx?Item=N82E16814130600
The GTX 460 is at least 3x better in every category than the GT430 so even running GT430s in SLI ($140) would still be slower and would cost more money too.http://www.hwcompare.com/8103/geforce-gt-430-1gb-vs-geforce-gtx-460/
Your best bet is either to stick with one 430 or pay extra (but not as much as 2 430s) and get the gtx 460 instead of doing 430s SLI.