WiFi N Gigabit Router

"I have a Linksys WRT310N, which has 4 ports of Gig-E and Draft-N WiFi. The antennae are internal, which looks nice. It can run the open source firmwares like DD-WRT. See this wiki article for some details.

$95 from Newegg"

You can extend a Time Capsule network with an Airport extreme and get that last last ethernet port. This has the added benefit of supplying an audio output and a larger effective network area if your machines are spread apart. It is an expensive solution for that last port . . . but it is very easy to manage from your mac. I have this solution running in my house. I have backups and a fast, reasonably secure network with remote speaker capability. I'm considering putting one outside on the deck in a weather proof box to supply music outside . . .