Laura K. Justiss - A Survey of Electronic Research Alternatives to Lexis and Westlaw in Law Firms is available on SSRN.
Academic librarians may find the following tables useful for teaching purposes:
Page 12 "Primary Source Alternatives to Lexis and Westlaw"
Page 15 "Court Docket and Case Information Services"
Page 18 "Secondary Sources for Topical Legal Research, Legal Periodicals, etc."
Page 20 "Financial, Business & News Information (including SEC Filings, Public and Private Company Information)"
Page 22 "Public Records"
Page 24 "Non-legal land Legal-Related: Patents and Trademarks, Science, Technology, Medicine, etc."
The article has other tables that in my view, are more firm specific information. It probably goes without saying, but I am sure that most of us think that it is important for academic librarians to know what other databases that the firms are using so that we can expose students to those sources as well.