yes and no.
the UV filter can come quite handy in the protection of lens.
The other thing is that it cuts of certain UV light esp in sky shots, or if you try to take at the beach.. it does have a difference.
(from photo.net) below...
For more effect added to sky shots.. u may wanna try...
Graduated Neutral Density filters
The sun is very bright; you heard it here first. Film can only handle a limited range of contrast. In a sunset photo, if you expose to capture color in the bright sky, the landscape will be black. If you expose to capture detail in the landscape, the sky will be washed out and white. So it equalizes the illumination of the land and sky.
The best graduated filters are square or rectangular. This lets you slide the filter up and down until the graduated region in correctly positioned for your composition. Tiffen makes some especially good glass graduated ND filters.
No. because...
well.. esp night shots, you may get an extra reflection, so just take the filter out. well it may or may not do good to all extent.
keep using and examining your pictures
ill see if i can post some comparisions if i have time
(freaking project at hand)