More Personalization with Windows 8

From Windows 8, you have Two Start Screen

1. Metro Start Screen
2. Desktop Start Screen

Both you can customize and personalize independently,

For Metro UI from the charms bar (You can hit WinKey + I) > Change PC Settings > Personalize > Start Screen, to change the color theme

Windows 8	Windows 8.1

You can use Ease of Access to make the Metro Tiles bigger.

For Desktop from the charms bar (You can hit WinKey + I) > Personalize or Control Panel\Appearance and Personalization\Personalization, to change the Desktop color theme, background.

Windows 8	Windows 8.1
	Control Panel\Appearance and Personalization\Personalization