Don't forget Infiniband
FCoE has a large mountain to climb to replace the SAN as we know it. Primarily on the latencies, but I also don't yet see a cost savings. Especially when you start to factor in needing redundant paths and separating storage and network traffic for performance reasons, as well as the cost of the 10GbE ports from Cisco. If anything will replace anything, I think it will be infiniband as the direction, NOT the network. Infiniband may be currently pricey, but those costs will drop much like FC has been doing, and will continue to do so as more and more shops look at it as something for other than HPC for infrastructure consolidation.