Question: Opening the command prompt ("cmd") on Vista into full screen causes the application to take up 100% vertical space, but only about 50% horizontal. Is there not a way I can make this fullscreen? If it's simply not possible, what is a good replacement?

Answer: 
For a replacement, you could look at [Take Command](http://www.jpsoft.com/tcmddes.htm), it has both a normal console replacement, and a windowy tool where you can open multiple tabs with individual console sessions.

![Take Command](https://i.stack.imgur.com/aSGeh.png)

You can of course turn off all those extra things so that you only have the console part.
You can use [ConEmu](https://conemu.github.io/en/Downloads.html) for `ALT`+`ENTER` fullscreen:

[![enter image description here](https://i.stack.imgur.com/pvTno.png)](https://i.stack.imgur.com/pvTno.png)