What are best materials to clean a road sport bike?

I use mineral spirits as a cheap and effective solvent/degreaser. Otherwise I pretty much just use rags and water.

Would water and, a rag, be safe for wiping down, JUST, the frame?

Pledge works really well for cleaning a frame. It doesn't dry the paint out and lifts dirt instead of grinding it into the paint so much. We used to use it for spot detailing on Porsche's too.

simple green.

I use alcohol free baby wipes on frame, rim, and spokes. They get almost any type of dirt or grime off. I use an old Tshirt for drying and buffing the frame.

If I'm cleaning the chain, rings, and cluster on the bike then I use a Tshirt until . I only use degreaser if chain lube is dry, filled with water, or has a lot of road grit in it. TriFlow is my lube of choice, and any excess simply wipes of with the Tshirt.

Right on. No need for water, detergent, buckets, brushes, whatever. Just a rag to wipe of the grime after the Pledge/MrSheen/whatever has been sprayed on to wet it, and another rag to buff to a great shine. The advantage is that dirt won't stick so tightly to the waxed surface. This assumes that the bike is not covered in huge amounts of mud and dried-on brake dust (which is worse than grease for getting on the fingers).