I think Twilight Princess looks amazing. The style and attention to details are incredible, and the environmental effects make it feel more like a living world on a real day/night cycle than any other game I've ever played. Wind Waker and Okami are both extremely beautiful games, and I love that cell shaded look, but that doesn't mean TP isn't beautiful in its own right and way. TP also have the incredibly stylized and stunning looking 'twilight realm'. Even Resident Evil 4 didn't look that good, not to mention polished IMHO. Also the rock-steady frame-rate on the Wii version really helps (since it's so under-stressed being a ported GC game), I hear the GC version has some frame-rate issues at points. p.s. technically it is still an extension of the Wind Waker engine, they just used it differently