I know projections can be specific to countries and even sub-national regions. However, I work all over sub-Saharan Africa and instead of always using WGS84 geographic system, I know it is better to use a projected system. Is there a general "best overall" one to use for this area of the world? There are so many to choose from. It seems like equal area would be best.
Amanda,
You could try the sinusoidal projection, aka the Sanson–Flamsteed or the Mercator equal-area projection. This would work well for Africa.
Sinusoidal projection - Wikipedia, the free encyclopedia
You may also find it helpful to learn more about coordinate systems, projections, and datums - these can be tricky to understand and are often dry topics, unless you find them interesting! But, it helps nevertheless to understand them:
What are map projections?—Help | ArcGIS for Desktop
http://web.gps.caltech.edu/gislab/HowTo/ESRI%20-%20Map%20Projections.pdf