The W3C‘s ESW wiki has just consolidated a listing of RDF and OWL tools. This SemanticWeb Tools listing contains references to about 70 distinct tools, some open source and some proprietary, in areas such as:
The best thing about this listing is that it is available in wiki format and therefore is updated frequently by practitioners in the field. My only complaint is that the listing does not include information extractors (IE) or metadata generators. At any rate, I highly recommend bookmarking this site and re-visiting it frequently.