The Collected Works of Shakespeare. www.psrg.cs.usyd.edu.aumattyShakespeare.
All the way from Australia, this site is one of many "complete" Shakespeares on the Web - and although most use the same source of electronic text, this is the best for technophobes.
Shakespeare on the Web is largely about doing wordsearches - who in their right mind would want to read all of Othello from a screen?
This site offers a powerful search engine, and explains how to conduct various levels of search. And it's fast: I discover how many times the word "whoreson" occurs in all of Shakespeare (34) in much less time than it's taken me to write this sentence.
So, whether you're looking for serious textual analysis, or merely the source of a quote, this could be the site for you.
The Grove Dictionary of Art Online. www.groveart.com.
At 34 volumes, the Grove Dictionary of Art is the biggest art reference work published. And it is now available online - all of it. That means 41,000 articles by 7,000 authors from 120 countries, covering all the visual arts, all cross-referenced, and thousands of colour images.
Unlike most sites reviewed here, the Grove is not free. Subscriptions start at pound;135 a year - but then the print version does cost pound;5,750. Opting for the online version not only avoids the slog of trawling the volumes - it also provides direct access to external sources (12,000 links to galleries, and museums). And there's a constant stream of new articles.