The latest version of Minecraft mod Sonic Ether's Unbelievable Shaders adds realistic, gorgeous lighting and water to the mix, so you get an interesting blend of blocky and modern graphics. Hit the source to download, though be warned the version with water shaders is in beta, and is said to be buggy and provoke poor performance. If you're not up for that, just check the video below and "ooh" and "ahh" away.
"Ether" says where he's previously ruled out including bump mapping (bumps and wrinkles and such on surfaces) in his Minecraft mods, he's now reconsidering. So if you're into that idea, there may be that to look forward to.