Honestly though, I could say the same thing about 10GbE. It's really hard to push 10Gb traffic, most laptops and users would have a hard time pushing 1Gb. The IB is a backend network and where people use it are to connect quick clusters of either VM or compute.
If possible, definitely do the Ethernet route to save headaches, but you won't find good prices for switches with lots of ports. That's where the IB world is cheaper for now. In a year or two, 10GbE will be cheap and people will complain about 40GbE and why they can't get 4 port switches under $1500.... And the IB world will be at $200 for a 36 port 40Gb switch.
Back to my original point, it is really hard to hit >1Gbps for normal laptop and desktop use. Laptops are mostly concerned about wireless speeds, not wire speeds.