Here are some of mine:

This I found on my computer just now. I did this puzzle about 5 years ago. It took me and my aunt 3 days. It was 1000 pieces and very hard.

This is the Zelda Puzzle I did a few months ago. It was hard despite only being 500 pieces due to the lack of color variation. Took me 6 hours.

This one took me over 30 hours. It was a pain in the ass because all of the pieces are pretty much the same shape and there are 1500 of them. >.< But the end result was awesome. It's framed now.

This one is 1000 pieces, and I think it took me around 16 hours total.

This Majora's Mask puzzle can still be ordered from Club Nintendo while it lasts. It's 300 pieces and it took me 2 hours and 30 minutes.

I just did this one tonight. It was 550 pieces, and it was much easier than it looks. Only took me 4 hours and 40 minutes.
While typing this, I forgot that there are no spoiler tags on TLW, so sorry for the large images... o_O