Almost every application you install includes fonts, though they aren't always installed by default, so you might check what fonts you already have with older applications that you haven't installed on this system.
If you're willing to pay for fonts, you can find a good selection of commercial fonts at
http://www.myfonts.com/. If you're looking for free fonts,
http://www.dafont.com/ is a great source for thousands of fonts. There are both free and commercial fonts at
http://www.bvfonts.com/ and
http://www.fontdiner.com/, and most foundries have their own websites as well.
You can also google for fonts.