The Avon Roadriders are available in inch sizes, they are by most reports a very good tire. Never tried the inch-sized Michelin Pilot Activ's but they look to be similar to the Avons.
I have had S11's and Conti's on as well. The S11's were also a good tire, see Lornce's post for the sizing. Wasn't as fond of the Conti's but tires are a personal thing.
I haven't totally made up my mind on the Avons yet. I don't feel completely comfortable at deep lean angles and I am playing with tire pressures a bit to see.