Gone are the days of Billy boy saying 640k will be enough, most systems I sell go with 4GB of memory, some with 8. Triple channel kits come in 6, 12 and 24GB so memory is going up and up and up. Sandy Bridge and Bulldozer plan to combat this with LR-DIMM's.
LR-DIMM's are a JEDEC version of the late MetaRAM tech - which basically faked a DRAM chip with a heap of small ones. LR stands for Load Reduced, and that's exactly what the buffer on the DIMM does.