Man this thread could get long //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
I will start off
pine - to soft , resonates like a beeyotch , not dense enough for enclosures , but cuts very easily. Good for structural frame work , but not enclosure walls. relatively cheap
maple and birch - I assume you mean maple and birch ply. It really depends upon the grade of each . There are grades of each that are void free , little resonance , and work great for enclosures. They are also lighter than mdf. But there are also grades of each that are not well suited for enclosures. Biggest draw back to these plys is price. Usually almost double the price of comparable mdf . Cut's pretty easy as well
MDF - It's cheap, dense , but quite hefty in the weight department. Rough on saw blades as it's not the easiest stuff to cut.
When building enclosures , your looking for a dense , strong, and managable substrate first and foremost. After that price and a few other things come into consideration
I'm sure others will chime in //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif