Of course there are a myriad of controllers out there, these days I use a Korg Nano Control Studio when I need physical faders to tweak a mix on the fly (which I often don't).
Anyway, I've just discovered the X-Keys range of programmable controllers: http://xkeys.com/xkeys.php, and bought the X-keys® XK-24 USB Keypad.
After just a few days, I'm suitably impressed.
Now I'm well aware that all this can be programmed using a standard keyboard, but I'm rather taken with having all my common key strokes in one place. When tracking or editing, I can now pretty much do away with my standard keyboard and rely on this nice tactile surface instead. You can programme it to illuminate the buttons (I have play/record illuminate red when recording).
Here's a pic of how I've set it up:

Works fine with a Mac and is compatible with Windows, Linux.
Bob