The first thing you'll notice on the new Photoshop CS 6 is the dark interface around the menu and tools. I didn't like it at first but now I'm starting to get used to it.
Photoshops reasoning is to keep the tools in the background so that you can focus on the image.
If you don't like this new color you can change it in the Preferences.
To do this go to Photoshop's preferences - Interface
Here you will see 4 shades to select from. You can select anything from a light gray to black.
But, if you're like me, you might like the new darker interface. I've decided on the black.
Want to change the canvas color? This too can be customized by simply right clicking and selecting one of Photoshop's shades or even customizing your own canvas color.