Beyond the mere fun of spinning around a virtual globe, Earthsim offers its users animated, narrated mini-documentaries that play through the program's interface, explaining everything from the geology of a particular region, to environmental threats. The demo version only lets you zoom down to a fairly high altitude, and gives you just a taste of the animated documentary features. Subscribers to the $25 service--and yes, it's an annual subscription--get regular updates to both the list of pre-produced videos, and the ability to zoom down to the surface, and even out to the moon and other planets of the solar system.
Despite the hefty system requirements--and the well-known free alternatives, such as Google Earth and Microsoft's Virtual Earth--Earthsim is the only option that includes real-time updates that show the actual weather around the planet. In addition, the animated educational component might make it more desirable for educators or parents than just a spinning 3D virtual globe that has a photo of your home in it, somewhere.
Note: This link takes you to the vendor's site, where you can download the latest version of the software.