EDIT 2: Come on you guys, I know reading is hard and all, but I am not complaining about the look of the game or bringing back any kind of argument. This is simply an alternative for those that weren't satisfied. If you like the way the game looks by default, that's perfectly fine. This isn't for you.
I know some of you guys are unhappy with the lighter visual tone Diablo III is taking relative to the first two games, and I think you will be very pleased by this. Someone has created a filter for the game using shaders that makes it look almost entirely different. I can't believe the difference it makes. I almost want to believe that the filter is making the original game blurrier than it was to fool me. The only downside is that the sharpening effects make some of the item text look really muddy, but I absolutely think it's worth it for the results (plus you can toggle the filter on and off instantly whenever you want in-game). The package comes in different varieties depending on how dark you want it to look.
I was going to post some screenshots I took, but I can't seem to get them large enough for you to really see the detail, so I would just recommend looking at the ones in that forum post I linked to above.
EDIT: Links for the lazy