I've had my Mac for awhile now, but haven't yet found out how to change the default program for opening a type of file. For instance, I want VLC to open my .wmv files instead of Quicktime player.
Right click on the file, go to Get Info. There's an option in the get info window to set the application to open it with (and optionally apply to all files of that type)
another thing i believe you can do is press 'alt' when you right click on the file you want to open - observe the Open With option change to Always Open With
Finally solved this, and of course is sooo easy.
I have tons of footage shot with the Sony EX-1 and EX-3 cameras and it was driving me crazy to having to right click and open with.. everytime I need to watch a clip. (Quicktime can´t play the files directly)