Maybe one other thing to consider -- I think its usually best to have a killer game idea that seems fun, then design around it (and select the proper engine), rather than simply "I want to build an engine with some capabilities, then I'll figure out what games to make later."

Have seen this with a lot of software "frameworks" (web, game, graphics, etc.). Nothing wrong with writing an amazing tech demo just for the hell of it, but then when it comes time to do "real world" tasks, the frameworks are often in search of a fitting problem.