Replacing multiple objects with one

Hi guys,
Thanks ahead of time for taking the time to answer.

My question is when creating a world in blender, is there a way I can replace multiple objects at once with one finished object? Kind of like a search and replace function? To be more detailed, let’s say I make a world with 12 crates that are now just cubes as place holders for a finished crate which will have seams and textures applied. When I have that one crate ready, is there a way to select those 12 placeholders and simply replace each with the finished crate? Or is there a better way than at that point literally going back and replacing each crate with individual finished crates?

Thanks so much!!!

Select all the objects you want to change and the object you want to change them to. Ensure this object is the last one selected so it is the active object. Then you can use Ctrl+L to link the object data

Demo: http://screencast.com/t/zPrezz1sVx1m

Omg i love you so much! Thank you richard!!