What kind of filter should i use for wide angle lens?

Recently, i had bought a Nikon 10-24mm lens.however, i'm thinking of getting another filter although i had bought a Hoya 77mm UV filter.

purpose for shooting: Cars, landscaping.

please advise me on this.

For the glare in the sunshine on cars, I would get a polarizing filter for digital lenses. They are not cheap! Landscaping with the sky included, a polarizing filter will also help if you shoot at the the right angle. It will increase the blue in the sky.

Definitely a polarizing filter! For cars? You mean removing reflections? Get a 77mm polarizing filter from Hoya, B+W, Cokin or Hama.

Here's a Lens Filter Guide - http://www.the-dslr-photographer.com/2010/03/buying-a-lens-filter/