I use movie posters here to illustrate my reviews, not for aesthetic reasons for the most part, but to use as markers (so readers can easily find their way to the film they want to read about) and memory joggers (so readers can connect my ranting with the images they have seen in the media and at their local flicks).
Most posters don’t add aesthetic value because they are (mostly) bollocks – contractually obligated layouts with crappy photoshopping.
I wish we lived in a world where movies were promoted with design like this:
Dirk Bogarde in Victim (produced and directed by Basil Dearden)
There are three more examples of posters from Dearden films at the Criterion Collection blog here. All wonderful.