Ubuntu 10.04 is running with GNOME 2.30 (development packages at this time), KDE Software Compilation 4.4, X.Org 7.5, and the Linux 2.6.32 kernel at its heart. Ubuntu 10.04 Alpha 3 is the first Ubuntu release to feature the Nouveau kernel driver for open-source NVIDIA kernel mode-setting support. Intel and ATI/AMD kernel mode-setting has already existed in Ubuntu. Lucid Lynx also uses Yahoo search by default and possesses the Ubuntu One music store plugged in via Rhythmbox. There are also other changes to be found in Ubuntu 10.04 LTS like dropping HAL (the Hardware Abstraction Layer) and better social network integration.
Already atop Ubuntu 10.04 snapshots we have delivered file-system benchmarks, Linux desktop benchmarks, and just this morning we published our findings with regard to Ubuntu's power and boot performance.
The Ubuntu 10.04 Alpha 3 release announcement can be found on ubuntu-devel-announce. The next planned development release is the Ubuntu 10.04 Beta, which is set to be delivered in mid-March followed by a second beta and release candidate before going gold on the 29th of April.