Android 3.0[Honeycomb] is dedicated for tablet PCs hence the design change primarily focuses in tablet optimization with updated UI.

Honeycomb is the next version of the Android platform, designed from the ground up for devices with larger screen sizes, particularly tablets. We’ve spent a lot of time refining the user experience in Honeycomb, and we’ve developed a brand new, truly virtual and holographic user interface. Many of Android’s existing features will really shine on Honeycomb: refined multi-tasking, elegant notifications, access to over 100,000 apps on Android Market, home screen customization with a new 3D experience and redesigned widgets that are richer and more interactive. We’ve also made some powerful upgrades to the web browser, including tabbed browsing, form auto-fill, syncing with your Google Chrome bookmarks, and incognito mode for private browsing.