In all my gamedev I've found that the best structure was how Lua does meta-tables. You can then use that simple mechanism to implement inheritance, component b

In all my gamedev I've found that the best structure was how Lua does meta-tables. You can then use that simple mechanism to implement inheritance, component based design, message passing or whatever structure makes the most sense for your game design. I'm personally tend to lean towards component based for reusability and performance but that's by no means a hard-and-fast rule.