How best to render a 3D grid? Hello I am new to Blender. I created a 3d grid using cylinders but it does not look nice. The grid lines are not regularly spaced. Can anyone tell me how to make it look better? 

You can see the blend file here.
http://www.imsc.res.in/~aagrawal/Schematic2.blend
Another way to create a 3d grid could be to use a simple basic cube:


add a wireframe modifier for the cube
add an array modifier on X, fixed count (eg) 5
add an array modifier on Y, fixed count (eg) 5
add an array modifier on Z, fixed count (eg) 5


Like this:



At least you can play easily with modifiers until satisfied...

edit:

I'll try to explain (as I got it) what Mentalist suggested in comments: you can avoid the wireframe modifier, using a "wire" material, which allows to save a lot of geometry at the expenses of... geometry, ie: material wireframe width is not adjustable but also in this way you save so many vertices. 

I'll also add the option to use a different base shape (a "3d cross" instead of a cube) to save quite more (unneeded) vertices, because using cube and arrays, all cubes share all their vertices... with the "3d cross" this is slightly better.