If you juice, then watermelon and/or cucumber are good choices, especially when the melons or cukes aren’t in the greatest shape – off-season.
Although sometimes I’ll juice carrots if I find a good bulk price, usually I let Bolthouse Farms brand do the juicing for me. I prefer to juice items that produce a lot of juice, since I don’t find any use for the pulp that I would enjoy. If I’m going to use the pulp, then I might as well eat the whole carrot.