No not even that!
I have default fonts for serif, sans-serif, and monospace. They're actually pretty good replacements, and most people wouldn't notice the difference. I actually like some of them better than their "websafe" equivalents. The strange thing is, Ubuntu comes with hundreds (okay, not hundreds, but a lot) of default fonts. Most of them are serif, some are sans-serif, and a few are monospace; but they look almost all the same to me. You wouldn't be able to tell the difference between a lot of them unless you actually sat down and examined them closely.
I've also installed a few fonts from Google Webfonts.