I use the plastic expansion joints in a tan color to match the color of the skimmer lids.
It also compliments the tan and brown colors in the coping rock and the tan and brown pebbles in the peagravel we seed into our concrete for the exposed aggregate look. I only place wood when I'm butting up against the foundation or an existing concrete porch.

See ya,
Kelly

Kelly, thanks for the quick reply. Do you have a manufacturer for the plastic joints? Have you ever had trouble with the plastic cracking or popping out after a few years?