According to the documentation you linked to, GL_TEXTURE_MAG_FILTER is used when "the pixel being textured maps to an area less than or equal to one texture element". This tells me that for rotation, this is the symbol to use in your case (i.e. when there is no scaling); set it to GL_LINEAR for the anti-aliasing effect.
Yup. That clears it up for me. Thank you for all your help, d7samurai. :)