Infinband already at 40Gbps / FC at 16Gbps
With Infinband already at 40G and FC at 16G, the Ethernet meat grinder needs to quickly increase its grinding wheel to adopt 40G Ethernet and not just sit back with the promise of 100G sometime in the future. We've seen this over the last decade where Fiber Channel has embraced higher speeds in a more incremental fashion (1, 2, 4, 8and now 16Gbps) at a much lower cost point than the "less flexible" Ethernet, which just offered 1Gbps and 10Gbps (take it our leave it).
The Ethernet community need to be more "flexible" to the faster changing needs of Data Center SAN's, they've made a good start agreeing to standardize 40G Ethernet (though with a few cries of heresy) and adopting the same physical layer as Infiniband (i.e ability to use the QSFP copper/optic modules). But we have to wait and see if Ethernet vendors offer this flexibility to customers or if they insist on sticking to the 10x dogma.