Are there specific types of plastic that are more "Clear" than others? I am looking for brands/types of plastic that are more "clear" than others.  I am not sure if there are any differences between types i.e., acrylic, plexiglass, etc, but I would assume that some are more suited for certain situations, and are made in certain ways, with certain materials.  

I am essentially looking to replace a couple of computer "side panels" so I would like materials that are very clear, and wont get beat up i.e., scratches and smudges such as one review I had read on Amazon that claimed their "Lexan" was full of non-removable smudges which sounds like a defect to me.

Thank you.
You're probably looking for acrylic.

Computer case manufacturers often use acrylic. For a recent example, the Thermaltake core P5 atx case uses acrylic. Also, according to this datasheet acrylic has higher optical clarity than polycarbonate and can be restored to full clarity by polishing.

Also, acrylic sheets can be sourced easily, can be cut with a scorer, and are light and strong.