im in the same boat, been trying to figure out which mobo and ram to buy for my upgrade. From what I see. The crucial 3200 DDR is best Value ram, being cheapest. The HyperX and corsair are probably the top performers. In alot of reviews the HyperX just fell a little shy of some timings that the Corsair could do.
Also in terms of XMS, I think it is better to get the TwinX kits. Because they are 2 sets of ram together that have been tested already to run dual ddr. Also they have faster timings than the XMS does. I read some reviews that said if you just grab 2 sticks of the regular XMS, you could possibly run into the problem of them not being able to work perfectly side by side. Im not sure how true that is but....Just passing on that info. But Both hyperX and corsair should be fine buys.
I am not sure what I am going to buy yet myself. HyperX is some what cheaper. In terms of how many sticks to get, I am not sure why so many people are just grabbing 1gb of ram, you really dont need that much. It seems everyone buys 1gb these days, not sure why. I have 512mb right now, and it is more than enough.