Typographic compendium available
The FontBook could be of great help for every web designer, who likes typography and has an affinity to design with type. The book has been confirmed to have the most complete digital type reference in the world. It has 1760 pages, with 32000 different typefaces, coauthored by Jurgen Siebert and Erik Spiekermann.
This font variety is amazing, but I think it could also lead to confusion, paging through such a reference. There are hardly people who will use even 1% of the fonts described there. You have to know, what you are looking for, before opening it.
Since buying the book doesn't include the fonts, you may have to pay more to acquire interesting ones. Not every one is legible on the web, so this is probably justifiable when you are working extensively with print media. Through @font-face we are now able to embed a variety of fonts on a page, but combining many is always a bad, so we are practically constrained by the number that would most make sense.