Bit Savers, who make available historically important software, computer manuals, etc.
Brainy Quote: a great, searchable source of quotations by famous figures
Cite U Like: free service to help academics to share, store, and organise academic papers that they are reading. When you see a paper on the web that interests you, you can click one button and have it added to your personal library.
Cook's Thesaurus: a cooking encyclopedia that covers thousands of ingredients and kitchen tools. Entries include pictures, descriptions, synonyms, pronunciations, and suggested substitutions.