When I go to France, I always take this book with me, for its hotel & restaurant recommendations and town plans, in a portable form. I don't buy one every year, and in fact the last one I had was the 2007 edition, so just out of curiosity I had a quick superficial look at the two of them. Here's a few differences - the 2011 version first, followed by the 2007 in brackets:
-- No handy bookmark containing explanation of symbols (included with all previous editions I have had)
-- 1862 pages (2075)
-- Includes "more than 4500 hotels" according to the back cover blurb ("more than 5100 hotels")
-- Includes "more than 3300 restaurants" ("more than 3600 restaurants")
-- 601 resaurants in the Bib Gourmand category - good food at reasonable prices (489)
-- 571 starred restaurants (527)
So - overall, fewer recommendations for your money, but more of the cheaper ones? Not sure if Michelin thinks the standards of French cuisine are slipping ...
Also - and I am not sure if this was due to Amazon wanting to source as cheaply as possible, and therefore choosing the French version, or whether Michelin has cut down on foreign versions - the 2011 version that I have just received is in French albeit with an introduction & explanation of symbols in English (and other languages), whereas my 2007 copy was in English (with introductions and explanations in other languages including French). You may want to check this out if French is an issue for you.