Lots of wonderful minimal themes on here, but I think this is the minimalist.
Minimalist details:
We only show the path for the selected item (which is basically how you read these details anyway)
That also makes it easy to see which item is selected so we don't need a highlight!
Keyboard shortcuts for matches (e.g. "⌘4") are harder to use than just up/down+enter, so I hid those
Uses the light weight of the system font (San Francisco) for that native, readable feel
Looks best with a medium amount of blur
Available in a wide array of colors
Downloads listed below, preview images beneath (I'm not sure how to show images inline any more…):
Almost white: http://cozy.es/PRYr
Almost black: http://cozy.es/eBRP
Almost alizarin: http://cozy.es/WjeE
Almost asbestos: http://cozy.es/4Jul
Almost carrot: http://cozy.es/NyKn
Almost clouds: http://cozy.es/QyXj
Almost emerald: http://cozy.es/AxKm
Almost midnight: http://cozy.es/qnEA
Credit to flatuicolors.com for the colors. Best with these appearance settings.
Enjoy, and let me know how these work for you. Thanks!