That link didn't work for me. It took me to a search with 0 results. Corsair is known make really good RAM, but it's also a little more expensive. OCZ is also good, so it's really up to you. Either would work for overclocking. Keeping with the triple channel scheme would mean a jump to 12GB. That's a ton of RAM and I don't see you needing more than that unless you plan on hard core video rendering or something like that. No game that I know of will get anywhere near touching 12GB. Better too much than not enough, right?

In reading the reviews I saw that some people are having stability problems with the OCZ. I found some Corsair for $15 more for the set of 3 DIMMs that is very highly reviewed
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145220. 1 or 2 of those I think may be a better choice.
Is the Raptor HDD you have now SATA or IDE? If it's IDE I would recommend getting a new SATA drive for the OS and programs and use the Raptor as storage. If it's SATA, then the Raptor may be faster than the newer inexpensive drives. Do you know what RPM it is? I like 7200 RPM drives and would not buy a 5400 RPM drive. I just bought a Western Digital 1TB SATA 7200 RPM drive for my computer and it was $95, so 500GB and less are very cheap right now. Honestly, though, it's probably about $20-$30 more to make the jump to a 1TB. With programs taking more and more space it may be a good idea to do that. If you ever plan on making your computer a DVR for you TV (which is getting more popular) I would definitely do that. But regardless of what size you choose, I've always had good experience with Western Digital.
P.S. I made a new category under Computer Topics called Custom Computer and Upgrade Support since none of my current topics covered this kind of stuff. I'm going to move this thread there after you reply next (that way I know you saw this message and don't wonder where your post went)