Gobe (now known as URTH) have created a reliable UV filter in a range of sizes.
Having a UV filter on your lenses is a bit like having safety glasses on your eyes, not only does it protect from dirt, dust and any scratches but it also cuts out a lot of light fragments that may shoot into your images, and neutralises blue haze that is caused by UV rays.
For an example of what this looks like, click here
Available in mulitple sizes 49mm, 52mm, and 62mm
