Circular polariser filter most usefull when starting out, Go for a good brand, Hoya,Kenko,B+W or Heliopan. Also this has the best effect when used 90% to the Sun for darkening blue sky's, giving contrast to clouds and for taking glare off the foreground in bright sun, Also for reducing reflections of water and glass but not chrome or mirrors and also for giving saturation to colours like woodland, water and foliage.
UV filters are only realy usefull for digital cameras as protection for the lens.