Flat has become the new trend in all design aspects!
I randomly came across this set of icons and I was immediately stunned! It’s flat, simple but not lacking details.
Click for the download link on deviantART
To replace icons easily on OS X Maverick, use the tool named LiteIcon. For earlier OS X versions, Candybar has a solid reputation. Both are free.
Here’s a screenshot of Launchpad on my Retina Macbook Pro 15:
Kan Yao 