Transparent grid shows odd irregularities when displayed.

I created a grid prefab with a plane and a texture applied to this plane. The plane was made in an external modeled and is centered at origin. I have a transparent png texture used to display the grid. I run into problems when it is used in game. The image doesn’t always show up correctly. Lines sometimes may be thin, missing, or seem off when viewed at angles. How can I get a nice and crisp image? (btw the image layer has 70% opacity in gimp if that makes a difference)

Here is an example of what going on, notice the lines and irregular drawing of the drug when viewed farther away.
photobucket sample of problem image

Look there : http://unity3d.com/support/documentation/Manual/Textures.html

Aniso level.