What's a "kettle"?!
Waterbuffalo is cool looking as very fast, but I have NEVER had anyone say they could handle. They seem to be for people who enjoy being scared.
Yamaha 650 is popular because it was fairly successful at being a reiliable Triumph- in looks, if you squint. Fairly dependable engine and a VERY versatile platform- they make good flatrackers, cafes, and also very popular as a chopper engine. Currently at
www.sidecar.com are some pictures of an older sidecar/kneeler with a Yammi 650 in it.
Too many good choices for restos; Hodaka, CB400F is just killer in the mountains around here, love the old scramblers... 160s are very popular, I've always wanted a 90S for some reason...