Ubuntu Linux 11.04 now uses the "Unity" user interface, which features a prominent "Task Bar" on the left hand side that acts as both a task manager in addition to a common application launcher. Shown on the desktop is LibreOffice Writer, the word processing program that comes with the new LibreOffice productivity suite which replaces OpenOffice 3 in previous versions of Ubuntu.
See also Jason Perlow's full report, Ubuntu Linux 11.04: A whale of changes for Canonical's user base.
Nautilus is still the default file manager although it now uses the context-based menuing system in 11.04.
Firefox Version 4 is the default web browser that ships with Ubuntu 11.04. As you can see the web browser menus appear in the top menu context navigation area, a la Mac OS X.
Virtual desktops can be paged through using the Unity Taskbar. Applications in the Taskbar automatically zoom to the correct desktop they are running in when selected.
Here's another search view showing installed applications.
Banshee is Ubuntu's equivalent to iTunes. You can connect and sync it with your iPod, iPhone and even Android devices. A built-in music store allows you to buy content from Amazon or Ubuntu One. You can also stream live music from Last.fm.
Here's how file management is represented in the within the Search interface.