I have just upgraded my G4 Mac mini to Leopard. I am intending to use it as a media centre under my television.
The upgrade went fine, and EyeTV 2.5.1 seems to work just fine under Leopard.
I am running it (currently) without a keyboard or a mouse and of course being a G4 Mac mini it does not have an Apple remote.
I do have an EyeTV remote, so when watching TV, I can use that.
In the meantime, I am using VNC and screensharing to control the Mac mini and will be using either my PowerBook or an UMPC to do the controlling.
It’s connected to my Airport Extreme (802.11n) by ethernet, so the fact that it has only 802.11g won’t be too much of an issue.
I have an (old) CRT Sony television, so I am using s-video to connect the Mac mini to it, so screen resolution is quite poor, but for video and images it seems to work fine.
If this works out, I will probably replace it with a newer and faster Intel Mac mini. This one only had 512MB of RAM, and I would prefer at least 1GB or more.
I will write more, as we see how it works out.