Whatever you think about movies, Roger Ebert
is a master of the short essay. His reviews and columns are lively, readable, and compelling -- even if you don't much care about the movie in question. Ebert meets art on its own terms, without not trying to fit into ideoology or theory, he always remembers what movies (and Drama) is for, and he always considers carefully what the work is trying to do. This lets him write about ideas, not just about the best way to spend $8.50.
For interesting comparisons, visit the wonderful movie review compednium site, rottenTomatoes.com. Much reviewing is silly or dishonest -- not just in Hollywood, but in New Media and academe as well.