My original grilles were Chocolate Brown, and the box says BR so I was tempted to stay original. I also like the brown with the walnut cabinet. it is the most subtle and conservative looking IMO.
However, brown matches none of my other speakers. Beside that, the market (and therefore value) in good condition L100s has gone from audiophile / listener to collector, and collectors want them for the "pop" they have with bright quadrex foam grilles.
Talking to Scott about what colors he sells most, he told me that orange is the top seller, closely followed by blue. Both have that pop.
I chose blue. My L65As are blue so they match something in the room, JBL used a lot of blue on monitor baffles, and blue just feels right to me. I like looking at the blue in the room, and my wife voted blue so that she could paint the back wall a dark blue and buy paintings of boats with blue in them. Done. She did not like the orange at all, nor brown, would have chosen black as her second choice.