Deriving my answer from the way it currently is:
Clicking anywhere on the layer's line (left from color well, on color well and on layer name) switches this layer to be active, but clicking on the checkbox (obviously) changes the visibility.
To be consistent, I'd expect a left click on the color well to pop up the color chooser dialog or have a different way to toggle the visibility, i.e. no single-left-click, which would be counter-intuitive as well ...
+1 from me for that idea. Maybe it would also suffice if the columns had a heading like in @dbrown2k's post (eye or lightbulb for the visibility, color pattern for color selection, etc.), then the check boxes might remain the way they are (my guess is that it's less modification to the code).
Seems like a good idea to me.
On the Linux variants, hitting the right target is much easier as it is in windows because the UI elements have much more spacing around them. I've made a few screenshots to illustrate this:
OTOH, the layer colors are more discernible on Windows since the coloured area on the color wells is bigger.