If you're in the market for some high-end DDR RAM, Madshrimps has a review of Corsair's TWINX2048-4400PRO 2GB Memory Kit that'll be of interest. At lower clock speeds, this memory will run with tight timings, relax the timings though and this still will hit some impressive clock speeds...
"What can possibly be said about Corsair which hasn't been said before. Their products are known and respected worldwide, as is their reputation for producing the highest quality memory. Their memory is the most consistent ever tested with every product to date either meeting or exceeding specifications. Today we test a product from their XMS Series, in particular the TWINX2048-4400PRO kit."