I heard that MSI cyclone has fan fins that breaks off really easily when slightly bumped when you are doing some stuff inside your case...
I don't think you an break them that easy. NEVER WORK WITH A HAMMER INSIDE THE CASE
. The fins might be a little more sensitive to bending but other than that the cards should be ok.
"..but what about a single 23' nvidia 1080p 3D monitor?" -Well that won't be a problem, but for more fps i would go with 2xgtx470. You will have an advantage when using a 3d monitor in demanding games. If i had the money, i would buy the best that i can. It depends on how much you want to invest in your video cards.