We seek to identify a limited amount of representative corpora, suitable for annotation by the computational linguistics annotation community. Our hope is that a wide variety of annotation will be undertaken on the same corpora, which would facilitate: (1) the comparison of annotation schemes; (2) the merging of information represented by various annotation schemes; (3) the emergence of NLP systems that use information in multiple annotation schemes; and (4) the adoption of various types of best practice in corpus annotation. Such best practices would include: (a) clearer demarcation of phenomena being annotated; (b) the use of particular test corpora to determine whether a particular annotation task can feasibly achieve good agreement scores; (c) The use of underlying models for representing annotation content that facilitate merging, comparison, and analysis; and (d) To the extent possible, the use of common annotation categories or a mapping among categories for the same phenomenon used by different annotation groups. This study will focus on the problem of identifying such corpora as well as the suitability of two candidate corpora: the Open portion of the American National Corpus (Ide and Macleod, 2001; Ide and Suderman, 2004) and the "Controversial" portions of the WikipediaXML corpus (Denoyer and Gallinari, 2006).