Fonts are very useful for a designer. Only if you would take into consideration the typography mania and you have a great argument for the intelligent use of fonts. The web safe fonts seem boring at a certain moment. With sIFR and other web technologies you can insert any font you want in a website and you can give the site a more interesting style.
So, let's say you aren't a web designer, you are more a graphic designer, you make quality logos and other interesting things. You gotta have a serious collection of logos, unless you are a pretty exquisite designer and you're making a custom font for every project you are working on. Thus being said, check the fonts, download them cause most of them are free, look for a readme from the author to see where you can use them and maybe buy some of these on the list which are premium fonts.