Don't know if anyone's mentioned it already, but powerline ethernet is often a great way to get fast speeds via ethernet cable, but without cluttering your home up with cables snaking around between your PC and the router. Essentially it uses your home's electrical wiring to send the data around, and it works amazingly well.
Here's an example I found that gives you two ports along with a pass through plug so you don't use up the wall's:
Granted, nothing works as well as true Cat6 or Cat5A cable going directly between the router and the end device, but this comes pretty close, and is way more reliable than wifi.