I missed this earlier:
Usually, most people have regular computers, with monitors, and keyboards. Windows is still the most popular OS simply because... it's the most popular OS. Macs are increasing though and VoiceOver is built-in with all OSX systems, though by default it's English even if you bought the machine in a predominantly non-English-speaking country and the OS language is otherwise set in that other language... you have to go find and buy/get your own voices for your language for VO. Shame, really...
Some of the Linux users on the Orca mailing list have been figuring out a safe way to turn their screens off because, with laptops, batteries matter. But usually there's the regular monitor and of course this makes sense if anyone is sighted in the house and they also want to use the computer.
Some people have a Refreshable Braille Display hooked up, even though the percentage of the blind population who are Braille literate is low, like 20% or something. They're hideously expensive. They come in different forms: some have 16 characters, some have 32. Some have one row, some two or more. They're like a mouse, you just plug them in and you have software on your computer that the Braille display talks to. It can usually also work together with the screen reader and screen magnification/zooming software.
Here's I think a nice demo thingie movie of a RBD, here hooked up to an iPad: https://www.youtube.com/watch?v=tVuLGrab9JA
These thing just sit as regular software on top of the same software most other computer users have. The screen reader software gets information from the applications running on the Desktop for example (so this is the OS or at least the OS's windowing system getting involved, not just the applications... you can see now why it's more difficult for, say, Firefox or OpenOffice developers than for Mac software on Macs or IE/Outlook/Office/etc on Windows). So if you want to write a paper on Windows, you'll still use Word; if you're writing an email, you can use Outlook, or web mail, or whatever.
There is a Linux distro however that's geared specifically to the blind, as a distro you can install from scratch without sighted assistance and with all the normal built-in accessibility stuff turned on by default: Vinux. But Vinux gets installed on any Linux-compatible computer.