Just my opinion here......having had most of the RAM already mentioned in this thread.
My machine had the DHX 2 x 1GB kit, CAS 4. It was quite nice memory and OC'd well......but the upgrade bug bit once again and I was offered enough for the DHX set to make selling them attractive. While I had them, I did push them quite hard.....and they never let me down. Had an Antec Spot Cool fan blowing across them.
I moved to the 2 x 2GB G. Skill kit that's been linked earlier in the thread. It was alright but unimpressive in its OC'ing ability. Maybe I got a poor set. Then 3 weeks into ownership one stick died. Returned that set and bought this set:
http://www.newegg.com/Product/...x?Item=N82E16820146755
That Mushkin OC's like a champ, very nice RAM. But I got mine when the price hit what is showing plus was had a $30 rebate. OC'ing it right now at 1.94V.
My "small" machine has 4 x 1GB Ballistix DDR2-800 RAM in it. OC's well....runs nicely with no huge increases in voltages.
I have used Kingston in years past......HyperX mostly. But, in all the RAM I've owned over the many years I've built and UG'd computers, Kingston is the only brand that I had consistent failures with....invariably one stick of a set would puke and die in a few months. Maybe it was just a bad 6-8 month stretch for Kingston at the time, but I'll never use that brand ever again. Just a personal thing......cannot speak for everyone, just my own personal experience. But with four sets dying on two different motherboard/cpu setups in less than a year, and never overvolted much at all, I'll stick with brands I trust.
Brands like Corsair, Mushkin, Crucial......although some stories lately about Crucial's Ballistix failures are becoming too frequent......and makes me wary about the sets I have in my little rig.
Someone mentioned the fast RMA from Mushkin and their nice CSR's, etc. I cannot speak about Mushkin and their returns, but I can about Corsair. I haven't had to RMA any Corsair RAM, but did have an issue with Corsair's Nautilus watercooling system. CSR for Corsair was very helpful and I got the replacement part in just a few days.....with a nice note inside. Cannot ask for any better customer service than that.......and they didn't want the old, messed up part back first. Puts Corsair up there in my book.