have written a short article on the latest version of Ubuntu although it is still only in the alpha stage it seems.
Although many of the significant architectural features like PulseAudio and GIO are still in transitional stages and aren't fully functional yet, Ubuntu 8.04 alpha 4 is still very impressive. I'm a big fan of D-Bus, and I'm very pleased to see it being adopted throughout the entire desktop stack in core components. I'm also very impressed with the relative completeness of PolicyKit integration, and I'm looking forward to the promised performance improvements and support for pausing file transfers that we should get when GIO is more mature. Many of the major pieces are falling into their proper places for Hardy Heron, but there are still some things that haven't landed yet. One of the significant features planned for 8.04,for instance, is a complete visual refresh, with totally new artwork and new GTK theme. The new artwork hasn't begun showing up yet.
Im not sure the new artwork would be a good thing mind as I quite like the current Ubuntu design, time will tell on that one.