Though DDR2 may be the future, DDR still has a long ways to go. There are many powerful DDR systems out there, and some of them are able to achieve very high FSB speeds, some beyond 300Mhz for RAM. The problem with this is that the majority of DDR out there is DDR400, clocked at 200Mhz. There is other ram out there, but very little that goes as high as that. G.Skill, a Taiwanese memory producer, is changing that
with their offering of a DDR566 and a DDR600 kit. PC4400 isn't all that uncommon, but the timings on this kit are impressive, and the amazing speed of 300Mhz (DDR600) is there as well. What's most interesting is that the faster-clocked kit does not come with any heat spreaders at all. The article goes into some overclocking aspects, and adding heat spreaders to the faster kit will surely let you max your motherboard out far before you max your ram out.