For those of your with large media collections and decently powered computers. Check out aflegg's excellent on-demand on-the-fly transcoding solution: mediautils saves the trouble of re-encoding and gives you beautiful looking, perfect playing media every time. With a decent upstream, you can also set this up to send you media while on the road.

Personally, if you're willing to invest just a little time to prepare things for the N800, it makes an absolutely fantastic media playback device.