I've used Voice Over to some extent also (once again, this isn't an exhaustive survey by any means). It does appear to be oriented to people with motor issues more than the blind.

As I've said a couple of times here (mea culpa), my gut feeling is that the philosophy is wrong. By building verbal control systems on top of (over-) visually dense user interfaces, you have to run just to stay in place.

It could be that the answer is an entirely different audio UI for computer management and then the replacement of standard applications with ones that are suitable for audio control (with perhaps a few buttons). Perhaps somebody has made an email app for blind people, but I haven't run into it yet. It certainly wouldn't be Outlook with a robot reading the screen to you. Probably the only way I could understand this at all is to attempt to produce one, writing software has the side effect of forcing you to fully understand a problem.