The OCZ EL Platinum Revision 2 1GB (512MBx2) PC-3200 Dual-Channel RAM (Model #: OCZ4001024ELDCPER2-K), is one of the absolute best PC-3200 RAM you can buy. For those with a smaller piggy bank, try Crucial Ballistix 512MB RAM sticks (Model #: BL6464Z402). They aren't dual-channel, but you can buy two sticks and put them in dual-channel mode in your motherboard's BIOS (provided that your motherboard supports the dual-channel RAM configuration). Crucial Ballistix will cost you about $30 less than the top-notch OCZ stuff, and run at some of the fastest speeds out there. Additionally, I've heard that Crucial Ballistix RAM and the MSI Neo2 Platinum motherboard is an uber combination. The Corsair XMS 1GB (512MBx2) PC-3200 Dual-Channel RAM (Model #: TWINX1024-3200C2PT) is a great value. I've heard that it's CAS settings are very flexible, though I don't think you can reach 250mhz with it and maintain viable timings. At $40 less, it is a good option for those who are less into overclocking.
My overall suggestion would be Crucial Ballistix Crucial Ballistix 512MB DDR PC-3200 RAM (2).
Cy6nUsX1, GeIL = good.
Mushkin quality varies tremendously with their series. It is cheap RAM, but go for the higher- to highest-end Mushkin RAM if you consider overclocking at all. Don't get me wrong though, Mushkin is good RAM, and the price is really unbeatable.
b3six, the #-#-#(-#) -- sometimes they don't include the last number -- are CAS timings. I'd suggest looking it up on Google because it is a long explanation. Alternatively, Anandtech probably has a guide to computer memory that probably includes an explanation of CAS timings.
<someone feel free to provide a link>