And who can
a) be bothered to lift carpets and floor boards and more importantly
b) get permission from girlfriend / wife / parents to do so?
The next-generation of HomePlug standard, called HomePlug AV is rated at 200Mbps. There's also a number of companies (NetGear is one) that offer wireless APs / Homeplug combo units which is a handy thing.
I want to move my "server" out into the garage. The signal from my firewall/AP at the front of the house isn't reliable enough without having to faff around with a repeater. I'm certainly CBA to cable it, so I plan to try a Homeplug AV set-up and see how it performs.