Font in edit box

When you type your response to a thread the font is completely different to what the real outcome would be. Especially the numbers look really funky and the whole structure of the text looks weird. Could we change it so that the font matches the font used on the rest of the forum?
This is how the preview looks compared to the actual edit box:

I had mentioned that the font in the CODE tag seemed to be proportional rather than fixed, but never notices that before because I'm so used to edit boxes not being WYSIWYG.