The brochures look the most impressive, for example Wisconsin-Madison with 36 glossy pages including a two-page spread on Jin-Yi Cai and the P vs. NP problem.
The thrill is in the chase for Cai and others in Theory of Computing. He describes his research with the language of an artist, drive by "elegance, internal logic and beauty." The usefulness of the findings in this field can often be transformational, but they may not be evident until decades later.Newsletters focus more on recent hires, awards and research activities. Rutgers, for instance, has a full page on new hire (and former NEC colleague) Joe Kilian. The profile even mentions Joe's work on the Franklin eBookman. "As a theorist, it was rather strange to realize that I could go to Staples and buy a device that contains actual code I've written."
The posters have a more specific function like advertising the graduate program or announcing distinguished lecturers. They can't really expect us to travel a thousand miles to see a single talk. I suspect the distinguished lecturer posters really say "We are a real department because famous computer scientists visit us."
Brochures, newsletters and posters all have the same true purpose of branding, so we think of those departments when we recommend graduate schools for our undergrads, faculty jobs for our Ph.D. students and when we fill out those questionnaires that lead to departmental rankings.
The departmental web page has become the true portal that potential students and faculty go to to explore a department. Most CS departments that home pages high on content but often low on visual appeal. Departments should put as much effort into the style of their web pages as much as they do for those brochures, newsletters and posters.