Office. I have both the Surface RT and the Surface Pro, and RT comes with Office. You get Word, Excel, PowerPoint and OneNote. And they are all desktop apps that run in the familiar Windows 8 desktop.
Surface Pro is a full blown PC in the form factor of a tablet. It puts all other tablets to shame as it is an intel core i5. It is extremely fast and once you get used to it, ipad, which I have two of, and every other tab, which I have many, feel slow and stupid.
The base apps in metro are pretty darn good. Simple things like the Bing Travel, or financial apps are better than any app I ever bought on any other tablet. I think a lot of you are talking out of your you-know-whats. Having a full blown computer in tablet form with a Wacom digitizer is awesome. Especially for things like Sketchbook Pro. Basically, it's Cintiq, only better, lighter and all in one.