I used to have the X300SE and let me tell you, it is not a very good card. If I were you, I would go with something else.
Like this:
X800 GT
http://www.newegg.com/Product/Produc...82E16814102575
6600 XT, with a bonus Age of Empires III
http://www.newegg.com/Product/Produc...82E16814130261
6600
http://www.newegg.com/Product/Produc...82E16814122237
I'm not really sure what your price range is or how much you're willing to spend but any of those cards will give you great performance - More than enough to enjoy SHIII to the fullest extent. If those cards are the only ones that you can choose from, I say go with the 6200 from ASUS.