I didn't realise it for a long time, but instead of relying on DNS or directly entering IP addresses, most machines in my home network actually self organise. Many of you will already know this, but for those that dont...
Most devices support a thing called Multicast DNS - apple devices also do this.
Here's the article:
This is why things like Transmission, SickBeard, XBMC and SSH keys are useful: you can simply point to xbmc.local:8080 and get to a basic remote control.
This lets you simply refer to whatever the machine is and start talking to it. On a local wifi network, it's great.
Ubuntu made this much clearer in some fashion - the first time you join a network, it should flash a welcome message. If it hears about a particular host, it should notify "xbmc.local is available" or similar, indicating a few machines it has detected.