Wow! Lots of opinions here. Polarizer is definitely a must-have. [Check your camera manual to see if it requires a "circular" polarizer; some do for the auto-focusing. Regular linear polarizer is cheaper.] For distant landscapes, particularly high in the mountains (in the mountains high?), get a UV or Skylight. [I always used whatever was denser, with a "light pink" color cast. It also warmed up portraits.] And get a lens hood to keep the glare off!