The ND (neutral density) filter is used for special situations where you want to reduce the amount of light the camera sees. You will very rarely need or use this filter.
The protector lens is for most part, just a piece of optical glass to protect your lens from being accidently scratched.
Many photographers use the circular polarizer lens as a lens protector.
You can find better prices than the ones you show.
Do a little shopping around.
My guess....from the model numbers you show....the filter size is 72mm. You need to verify the filter size for your camera before shopping around.
....
Hi, Thanks for your help earlier today, I decided on the Panasonic FZ20, but...
How necessary are either of the filters for the Panasonic FZ20?
ND filter DMW-LND72 $35 Reduces the amount of light hitting the lens without affecting the color balance
MC protector DMW-LMC72 $50 Protect your lens from the elements; has no effect on photo quality
Thank you.

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