I agree with the folks who have nominated the JLC MUT -- it's one of my very favorites, and I love wearing it -- very pure expression of simple and clean design, and tough to pull off a movement that thin!
At the end of the day, though, for me it's this one:

And I do mean _this_ one -- RG, silver/white face, anthracite Romans, flipped, dots, 12-sector soleil, rhodiated hands with blue rings...
Best,
Gary G