The Knowledge Areas in the Business Analysis Book of Knowledge (BABOK) are a very good representation of the skills and knowledge needed to move up in the BA career path.

Business Analysis is a broad field though, so every BA does not necessarily need to be an expert in all the Knowledge Areas. Depending on your strengths and career goals, you may want to focus more on a certain role within the BA profession - whether requirements analysis, or business process modeling, or usability expert. There is a very good description of different roles on this site, under 'The Profession' tab, you'll see a 'Roles' page with descriptions of the variety of roles possible. Each role would require a bit different skill-set, but most roles require some understanding across all BABOK Knowledge Areas.

Sandy