Hiya everyone, just thought I'd add a couple thoughts on this as well.
Construct 2 has 2 types of text objects, the Text object (
http://www.scirra.com/manual/116/text) and the Textbox object (
http://www.scirra.com/manual/117/textbox), the former being more commonly used.
The Text object allows you to change the font both from within the properties section and also during runtime, where you can change the font used by the object dynamically.
There's also the "Set web font" action for the Text object, where you can specify a url from which to load a web-based font, such as Google fonts.
This is awesome because Google fonts are awesome. Many people already have them installed on their computers as well, since they are free. Plus, Google's servers being as fast as they are, if people don't have them already, it's a very quick process for them to get the fonts installed.
Others may disagree, but I think it helps to use Google fonts as a standard for the above reasons.
As for the Textbox object, from what I recall, it can be styled via CSS in the HTML page used to view the game. Perhaps others can correct me on this one, but there definitely isn't a font property for it.
Hope that helps.
-DavidM