what should i get for my cosmos s

Get a decent CPU cooler. Mugen 2 or a Xigmatek s1283 and assorted copies would be a good choice.

Why not an assorted baybus ?

Maybe a Hotswap drive, if you're into that sort of thing, and 4 sets of molex LED lights, 2 shining in the way, one out of the extra fan bay, and one at the top left, behind the mobo, gives a nice glow. Same with cathodes, however you'd only need 2.

Hope that helped.

4GB of ram?

Cooler. Most definitely.

thanks. yeah a cooler was one of my considerations. thanks guys. it's either cooler or RAM....i can get cathodes for free from a friend but it's not too important to me. i however need a short cooler for the cosmos because u need to remove the fan for the big ones and i don't want to do that.

any suggestions on coolers?

For a 92mm sink? Ultima 90. Performs within 2-3*C of a TRUE.
http://jab-tech.com/Thermalright-Ultima-90-pr-3852.html

maybe get the side window they provide for the case. That way you can fit a bigger cooler. That will be again at the expense of your side case fan but in exchange you get a view. =)