I have the ninth edition of the Encyclopaedia Britannica (1875). And I also have the eleventh edition (1911, with 1922 supplement), which I prefer for its greater coverage, its thin paper and its leather binding. I don’t begrudge the four-and-a-half metres of shelving they occupy. It’s handy to be able to look up Primitive Methodist, or Poughkeepsie, or Piranesi in these time capsules.
You can get the same information — though not the pleasure of paper and binding — from a website. The unnamed authors of this site have scanned and OCRed the huge 1911 text. The presentation is rough, the navigation is basic, but the words are there. I hope that one day all this text can find its way into a hypertext database, like the modern Britannica.
Update, August 2013: The 1911encyclopedia.org website has gone, superseded by the ongoing Project Gutenberg efforts to produce accurate versions of the work in various digital formats—see the links at the bottom of this wikipedia page.