[slodave]

UV filter will help a little, but not too much. It does cut down the UV light and also will cut through light haze, clearing up a shot. UV filters are dual use. The UV side and also, as a buffer in case you drop the lens and it hits on that side. Most likely the lens glass will be okay, but the UV will be a goner.

The kit lens that I use happens to be sharper than one of my dads good lenses, so much co, that he replace his lens. The glass in kit lenses should be fine. They just usually lack all the bells and whistles.

Noise, not grain... Noise is produced by digital cameras, grain is a film artifact... That aside, Lenses don't cause noise, they can't. Noise is due to ISO settings. The higher the ISO, the more noise that will show.

A good filter to get is the circular polarizer.. Though, they can only be used 90* perpendicular to the sun. A variable neutral density filter is good too... But it won't increase "color" or saturation.