Westlaw has many state and federal opinions in PDF original image format. Notice the hyperlinked PDF icon at the top of the opinion.
The Moritz Law Library also has a comprehensive set of case reporters containing judicial opinions from the federal and state systems. These volumes are located in the library's State and National Collection. See the law library map.
Bloomberg Law provides comprehensive coverage of federal court litigation documents, the same coverage available in the Federal Courts' PACER system. From the main page, click on the "Litigation Intelligence Center" at the far left. From there, locate cases by "docket number" and court or use the advanced search function for additional options.
ABA's Preview of United States Supreme Court Cases: contains merit briefs for recent cases, as does SCOTUSblog
See Bloomberg Law for access to federal court filings, including circuit court of appeals briefs.
While some state court litigation documents are available on Bloomberg Law, often only a listing of documents filed is available and sometimes not even that. As an alternative, check the clerk of court's website in the county where the case was filed.