I also have a soft rubber hood that flips backwards. I mainly use it if I am taking pictures through glass and I can seal out light reflecting from behind me. The polarizing lens will help with this as well. I usually leave my hard plastic lens hood on though.
One thing to check for is the coating on the surface of the glass. Many really cheap filters are uncoated, meaning they do not have anti-reflection coatings and can cause weird flares, and strange light difractions in your pictures. I often refer to this site for information, their library of articles by pro photographers is quite extensive.
http://www.photo.net
they have an excellent FAQ section concerning filters and their uses.
http://www.photo.net/photo/filters
Give these a try. The forum is huge and you can find articles and conversations about nearly everything concerning photography.