I need to free up some cash (I've been spending on lenses again) so will probably have to sell a pair of bins. The three currently seeing the least use are my 8x20 Ultravids (near mint condition), my Leitz 8x40 Trinovids (well used but still great optics) or my recently acquired Nikon 9x30 roofs (I know very little about these). So what do others think, which would you part with, and which will give me the best return?