For just one GTX 470 a good 550W PSU would do, if you wanted the option to add a second then it would have to be a 750W.
The choice for good, high efficiency 550W PSUs is not that great on newegg TBH, so you should probably go for this for only one card:
XFX 650W XXX Edition 80Plus Bronze Modular $90 ($30 rebate) http://www.newegg.com/Product/Product.aspx?Item=N82E168...
That thread looks really old to me - 2007, so I wouldn't pay much attention to it as loads of power supplies have been released since then.
As for newegg reviews saying that it has killed a motherboard, everyone has bad luck and that is probably all it was.
That Corsair is a bit better than the Antec Truepower, it is more efficient and has a longer ATX12V/EPS12V cable (60cm) compared to 54cm on the Antec. It is up to you if these things are worth the extra money. For most people they will both last as long and be as reliable and quiet as each other, both units are built by Seasonic after all.