Someone mentioned this above I think, but whatever you get, you can get or make an adapter to allow you to hook up other stuff. The problem with the cigar lighter style on a motorcycle is the vibration and wind and leg motion tending to knock 'em out. That's probably why Moto Guzzi put theirs under the seat, and why the FJR's is in the little locking box at the left of the dash.
Powerlet is more secure against wind, vibration, or rider motions, and BMW tends to put them where they are more easily accessible on the outside.
I personally like the SAE two pin connector and I have a fused pig tail at my battery. It doesn't intrude on the appearance, it required no cutting or modification, its capped when not in use. You can use it for a battery tender if you want. Make sure the fuse you use (and the wires of the pig tail) are up to the task you're asking it to do. I don't add a lot of heavy drawing items, like lights, big horns, etc., so the SAE 2 pin fused pig tail works for me.