Can I use 16GB memory card in my Nikon D80?

I'm using 8GB class 10 SDHC card right now.

Added (1). My camera is almost 6 years old and does NOT have a video function. I only want to use it to take pics and want a fast card - Class 10. The owner's manual says to use only up to 4GB card, but I've been using San Disc Extreme 8GB for a long time.

Your camera is supposed to be compatible with any SDHC card, so a 16GB card should work. I would however avoid any SDHC cards that allude to being UHS compliant as these may be problematic in your camera!

Yes.

Just be aware of the following suggestions to make your pictures last.

http://keerok-photography.blogspot.com/2011/05/how-to-keep-your-memory-card-healthy.html

Sure you can, but if your going to keep photos on the card for an extended period of time then I would consider 2 8 gig cards and change them out so if one became corrupted you would not lose everything. If your doing a lot of videos then the 16 gig would be the way to go, avoid SDXC and use only SDHC, PNY or Sandisk has always been my choice, stay away from generic's, they are not reliable and corrupt quite easily. Talk with you later Bo