I worked with Suitcase Fusion 5. I created four separate libraries.

As an example, find my Library #1:

I first applied the Vox-AtypI system coupled with a shade of the Sanders/McCormick system, Erik Spiekermann's FontShop system and alternate contemporary systems.
I also subdivided the Vox-AtypI system with individual historical designers, art movements and geometric (weight, width and else) and stylistic properties.

I use Suitcase also, since version 2. For many years I have organized my fonts alphabetically, in folders to be loaded Temporarily as needed. For basic fonts, which are the 35 which come with most Postscript printers along with fonts I use on an everyday basis such as Helveticas, Garamonds, Centuries, Futuras, Pi fonts, etc., I have in a set called, of all things, "Basics". If I have a large project which uses many fonts not a part of the Basics set on a recurring basis I will set up a special set for those fonts. If the project ever returns for revisions then I will have the fonts all set up and ready to go; just reactivate them.

Suitcase makes life in the type-users world so much more efficient. I could not get by without it.

I use Suitcase too. I keep it organized into main folders of font type, then foundry. At one time, I did have a main folder for MultiMaster fonts. I suspect one day, I'll be pitching the entire ps collection too like the MM collection, when/if it no longer works in the mac OS.

> By client/job?

That method can be handy for clients that require you use a specific set of fonts (for example a corporation that has a font list you must stick to). Especially if you have multiple versions of some fonts and must use a specific one on jobs for them.