The best looking sub is the one that can be hidden in the room with absolutely no indication of its function.
Failing that, my favorites are the old M-Design Eleganza line, the Bella (Aurasound NS12-794-4A underhung neo motor woofer, 500W Class G amp).
and Godfather (Aurasound NS15-992-4A underhung neo motor woofer, 1kW Class G amp):
Here are my three (two Bellas and one Godfather), prior to setup, as part of a big mess of audio crap:
That said, I'm shortly to dismember the Bellas and use the Aurasound woofers for flanking sub/stands under my new mains. (The Aurasound woofers have few, if any, peers. They're simply spectacular.) The cherry, alas, doesn't go well with our other furnishings.