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You can cut down on the clutter in your Blocks screen by turning off Block Access Rights (System Menu -> Groups -> Modify) A group that doesn't have access to a block will not even have the choice of the block being visible on the Blocks page. I use this to cut down on a lot of my clutter, the only person who has all the blocks on the Blocks page then is the webmaster (who sees all by default).
Hope this helps!