I wanted a switch+router capable of 10 gigabit speeds and everything in the market was expensive.

So I got a commodity PC ($400 Dell PowerEdge T30), put Linux on it, and then stuffed it with a 4 port 2.5GbE card (X8 slot, $150), a 2 port 10GbE card (X16 slot, $150), and a 4 port 1GbE card (cheap). Plus the built in 1GbE port.

It is capable of routing to the Internet at 2.5Gb speed just fine and then switching the rest of the ports at 10Gb speed. Getting a dedicated router/switch with this many ports would have been north of $1000, and probably a lot more of a nuisance to administer/maintain than Linux.