Powerpoint: The most useful addition to Powerpoint is the ability to broadcast a presentation without setting up a Web meeting. You can share the presentation to a Sharepoint workplace, if your company uses Sharepoint, or to a Microsoft Windows Live account. (The Windows Live option will be free.) Then you can invite others to view the presentation. They'll see it in their browser and won't need to have Powerpoint installed.
The latest version of Microsoft's presentation tool adds some nifty new 3D transitions, like the ability to seemingly overlay your new slide over the previous one or to dissolve from one slide to another. Here's a video that shows most of them in action.
Powerpoint has ways to go to match some of the transitions that are possible in Apple's Keynote software, though, like the ability to rearrange the objects on one slide into a new organization on the next one.
Powerpoint 2010 makes it easier to "borrow" an animation from a slide deck that you really like. You can copy the animation and apply it to objects in your own presentation.