Basically you have Continental,Panasela and Schwalbe are the most popular tires .
I use Continental travel contacts,I can't say how good they are in the 700c sizes as I have 26x1.75 tires.I can say that I really like them in my tire size.
Others like Schwalbe marathon supremes.
As for size I would say at least a 32mm up to 40mm width depending on road conditions and if you plan on takeing it off road at all.