[OmegaZero_Alpha]

Keep an even number, I would reccomend getting either 2gigs or 4gigs. Always an even number of Identical sticks of ram, try to keep it at 2 sticks as 4 sticks will be slower that 2 yet faster than 1. This is because Dual Channeled ram is always twice as fast as single-channeled ram of the same size and frequency.

You also want to keep the ammount of ram's FSB into consideration. (for example, if you want 2 sticks of 800mhz ram, you need a 1600mhz fsb for both the motherboard and your processor) (don't quote me on this, but I think dual channel cuts your FSB requirements in half?)

If you are looking for recommendations, than hear ya goe:

http://www.newegg.com/Product/Product.as...6813128080
http://www.newegg.com/Product/Product.as...6820227249
http://www.newegg.com/Product/Product.as...6819115017
http://www.newegg.com/Product/Product.as...6819115017
http://www.newegg.com/Product/Product.as...6835100008
Full ATX case, plug every hole with a good fan (get a window and some lights if that is your thing). I don't pick cases for people.