If you can easily RMA them, some regular Samsung DDR400 are the best value for your money, as they use UCCCs and sometimes go as high as 290MHz at 3-4-4-8. You may be unlucky though and get some that only do 220MHz or so.
I'll be getting these G.Skill:
http://www.newegg.com/Product/Product.asp?Item=N82E16820231032
They're only DDR400, but on a German forum several users report 260+MHz at 2.5-3-2-5. No one reported theirs not hitting 250MHz, and not everyone tried to max theirs out.
Here's a link to the thread, first post has a summary of all overclocks proven prime stable with a screenshot. There are some more reports later in the thread since the first post isn't being updated anymore. If you need to, use a translator to read the last couple of pages.
http://www.forumdeluxx.de/forum/showthread.php?t=177162