Via OAN, JISC in the UK has done quite an extensive survey of scholarly communications patterns amongst various disciplines. The report is a rather large 92 page word file. I haven't read the report in detail yet, but a quick glance tells me it is very useful, covering at a very broad level issues like discovery tools, journals types preferred and OA-related practices.
A quick hit from the press release:
Among the many findings of the report was the discovery of the importance of e-prints (pre- and post-) in the physical sciences and engineering, the broader mix in the social sciences and the particular importance of books in languages and area studies.