The DDR2 memory that will easily run is 533/667/800/1066 up to the 8gb max. seen for that model. " dual channel DIMMs DDRII 533/667/800/1066 up to 8GB" http://global.msi.com.tw/index.php?f...sc&news_no=620
1066 is the fastest supported speed while you can run either without problems. With prices having come down over the last few months you can go for a good set of either. Higher voltages like 2.2v often point at pre-oced memory however over going with 1.9-2v.
The supply at the bottom leaves a large gap between that and the board with the cards up about half way on the board itself. There's no worry about any card at all hitting the supply.
For a cpu cooler the higher prices seen on the Zalman CNP9700 copper arrayed 110mm blue led fanned cooler are worth it for many while ThermalTake is another good brand seeing lower prices on their line. This will depend on where you can order from while the links here are at newegg and xoxide.com
For a look at the Zalman model, http://www.newegg.com/Product/Produc...82E16835118019
Xoxide sees the same for $1 more at http://www.xoxide.com/zalman-cnps9700-cu-cooler.html
For a large copper hsf by ThermalTake seeing a smaller 92mm fan, http://www.newegg.com/Product/Produc...82E16835106075