I don't attend WGU yet, but I can tell you that they provide a webcam for exams. Since there are a lot of papers being written, you'll definitely need Word and likely Excel and PowerPoint. I haven't heard whether they'll take an alternate such as OpenOffice.
You should have Word. They want documents to be sent to them in .rtf format. You will also need Powerpoint. I know a lot of people use Macs, so either works equally well with Taskstream, apparently. As the previous poster said, they send you a webcam when you enroll for any objective assessments you need to complete.