Check out fellow voxel game Ace of Spades[1], Windows and works great on Linux with WINE. It's a FPS with beta 0.54 out this week. Really fun and interesting maps. You build just like in Minecraft, but also fight for to find and return opposing team's intel to your base (basically CTF). Customizable maps, sniper-rifle scopes and more. Also, it's free.
I don't know why, those unlit caves have some eerie feeling to them (e.g 3:15 to 3:40). They look really nice. I suppose they're randomized but they really look organic/mineral/geological in their shape. There's a reminiscent feeling of Parallax's Descent to it.
Totally, and it gives me the one percent hope that it may also inspire game companies to make new forms of games. Every major game looks exactly the same to me these days.
[1] http://ace-spades.com/