I have been away from OSX for a long time now. Since my company bought me a MacBookPro recently I had to move back in and get used to the environment again. I have to admit that one of the first things I missed was AeroSnap from Windows 7. I started immediately to look for tools that would replicate some of the features. I came across two options and started using them both for testing.

Divvy – Divvy was one of the first tools I found. Divvy is great as it gives you the option of splitting windows onto multiple parts of your screen. It has a very nice interface and allows custom keyboard shortcuts. Divvy is also shareware so it is not free.

Shiftit – Shiftit is a good tool that offers the basic functionality with a minimal user interface and less options. It does come with keyboard shortcuts already configured and this would be an extra step on divvy. Shiftit is free.

I would recommend that you try them both and decide which you like better, but either way you will be more productive.