I think it's the color from these cameras, at least in part, that has always gotten into me.
Agreed the colour outputs are pretty amazing, but I think the power of the Sigma is in how it renders contrast (esp. micro-contrast) and tones. Hence, why I think Foveon images make for very unique and pleasing black and whites - and what really does it for me.
That was natural light from a large window ... although I did apply a vignette in Photoshop and bumped the contrast and the saturation of a few colors.