For the topic, think of something interesting, something that could link up with a project for a different class (I'm ok with double-dipping), or just something you've been curious to see as a map. Anything goes -- any topic is fair game (well, provided it won't get me in trouble).
Single variable maps are the easiest (and what I recommend). I will, however, let you make a bivariate map (2 datasets). Three or more datasets on one map are prohibited for this project (they get logarithmically more complex). Just one word of caution on bivariate: don't get caught up trying to answer a question with the map (i.e. don't think of this as a GIS project where you need a map to show a result). For this class, the *map* is the key component. Doesn't matter if the topic has been done before, just so long as your map is fantastic. Focus your energy on the graphic not the data.
In order to make the map you must have data. Really search for the data before you settle in on your topic. This is often the "make or break" step of an idea. If there is a topic you love but can't find any data, let me know and I'll do some sleuthing as well. And Joy Suh, the Geography-oriented librarian at Fenwick library is also an excellent resource (for both data and ideas). I recommend seeing her if you are stumped. One last approach is to find a bad map of interesting data, and set about making it better (much, much better).
To help you nail down your idea (and communicate it to me) I want your to write a proposal. It needs to be a well-written blog post of around 500 words covering the following points:
-map subject
-reason why this is your pick
-map audience
-type of map you're envisioning
-scope of map (world? Virginia? Dorm room?)
-data specs (note where the data is from, the year, the size/complexity of the dataset, and the apparent accuracy)
-basemap needed for map
-expected production steps (be realistic and calendar focused)
-challenges you perceive