I have 5 different images one each for diffuse, specular, reflection/refraction, normal and illumination/emission map. Can someone please help me to set-up cycles material node including all the 5 maps to get the best physical render as possible? A screenshot after setting up all the nodes would be much helpful.
Here is how the maps you mentioned are usually arranged.
The diffuse texture is just plugged directly into the color of a diffuse shader. The diffuse shader is mixed with a glossy shader using the spec map as a mix factor; for further control of the specularity I stuck an RGB curves node in to adjust the falloff curve, that part is optional. The normal map is put through a normal map node which is then plugged into the normal input sockets on the shaders. The emission map is plugged into an emission shader, which is added to (not mixed with) the rest of the shaders. If your emission map is colored, plug it into the color of the emission shader, otherwise plug it into the strength and set the color to whatever you want.
Note: make sure all maps which are used to drive values (e.g. specularity), not colors (e.g. diffuse color), are set to non-color data.
I noticed that you said you have a specularity map, and a reflection map. But I am not quite sure what the difference between these two maps is, since for cycles (as in the real world), gloss and specularity are the same thing. And technically all surfaces you see reflect light (you couldn't see it if it didn't reflect light to your eyes); though what people usually mean when they say reflective is glossy.