I really dislike the Enlightened theme, and yet it's the default theme that everybody uses when they can't be bothered to change it, improve it, or build their own. So I made a simple replacement theme called "More Enlightened". It should drop in perfectly and immediately improve the look of your interface. I mostly got rid of all the gradients, made it less grey, and improved the accent colors. It also has a modernized button style, and added "invisible" button styles (which I find I need all the time).
Please replace all instances of the Enlightened theme with it. ;D