KeyBar Key Organizer
The KeyBar is a modular key organizer that works like a multi-tool for your keys, with the side benefit of stopping all that irritating jangling noise. It can accomodate up to 12 keys with the provided sets of screws (which you can change out at will), or you can buy a set of their extension screws to up that number to 14, 24, or even 28 keys.
The KeyBar comes in a variety of materials and designs, and thus a range of prices (anywhere from $45 to $100, depending on which one you choose).
(Note: If you've got any weird keys you're not sure will fit, check their FAQ page for sizing details.)