Logitech has cleared out all the older music stuff from their site. You can buy from independent retailers if needed.

Server: Rob's got the ticket here.

Server OS: Tony's choice.

For audio on the server end: Nothing else makes sense for someone like Tony besides Logitech Media Server (formerly SqueezeServer, etc...) They may be ending the product line but it's still "the only game in town" as far as quality music streaming also capable of serving a collection of quantity.

For Video on the server end: 2 choices, IMO.

The first is "nothing." Don't run any video streaming software at all and instead simply supply SMB/NFS/whatever shares that clients can connect to and stream from.

The second option is again back to something Rob mentioned. Plex Media Server. This will have a client requirement, but you may be able to use any DLNA client.

Now to clients...

Music: Absolutely keep this a dedicated music-only device. In other words, not a media player that would otherwise be connected to the video output of your TV. Either a proper Squeezebox or a more general-purpose device running software-based Squeeze-compatible player, such as any iOS device running iPeng. When it's not playing music you can use something like an iPad to show a slideshow.

Video: Now we're into problem territory. There's not a single solution at this time that I can recommend head-and-shoulders above the rest. The PS3 and XBOX devices can play back some content but leave a lot to be desired. Stand-alone media players all have a number of issues. You can use a small silent PC and run Plex CLIENT on it. That might be your best bet.

But you can also try the Plex app on one of the higher-end Roku boxes. Or a WDTV Live if you went the SMB route.

And FINALLY...... If you wanted an alternative you could wait around a little while longer and see about installing Windows onto that server, running Windows Media Center and then pick up one of the forthcoming Ceton extenders. Keeping with the suggestions above for music however. Ceton also has their own server with built-in tuners if you want/need that sort of thing. XBOX 360 can also act as an extender today, but again, YMMV.

Everything above except the iOS devices can work with an IR remote. iOS devices themselves make the best music remotes for operating on Squeezebox/LMS.