I modified ENBSeries so that it works well with Diablo 3. Essentially this tweak works with the default in game render engine to enable effects that are supported by DirectX but may not have been implemented- mainly SSAO and Bloom/HDR lighting effects.
I am still tweaking the settings but have it at a point where it darkens the shadows slightly and boosts the lighting effect. Although it isn't anything groundbreaking I feel it makes a significant impact on how the game looks so I decided to share.
Install is easy- simply extract the contents of the file to the Diablo 3 directory and start the game. When the game is loaded press "Shift-F12" to toggle on and off the effect. Note that this only will work with DX9 and a 32-bit client of D3.
http://dl.dropbox.com/s/td3wc6pby5kf2uv/ENBDiablo3.zip