Curious about file formats

I know this seems odd but I have spent several hours looking for code snippets and loading bits for various types of models. Right now as a C++ coder wanting to create a good toolkit for myself, I am looking for someone to clarify the differences between a few file formats. Right now I am looking more at the .MD2, .MD3, .MD5, .OBJ, .3DS formats than anything else. I just haven’t been able to find a document that simply states the following:

  • Which formats are the best for animation?
  • Which are the smallest?
  • Which are the limits for each sort file format?

Simply put, I cannot figure the differences between all of these formats. So far I can make the models I want in Blender but I am desperate to get it to a format where I can load the file easily and start using it. So far I have code for most of these formats but I wanted an opinion on how I should be concentrating my efforts.