I got a used 80-200 Nikkor for relatively little (although I would have taken a Tokina/Sigma zoom as well). The main gripes I have are (i) size (it doesn't fit into my camera bag anymore which gives me all the more reason to sell it and get a different zoom lens), (ii) zoom range (which is partly personal preference) and (iii) AF speed (which can be slower as the lens is a bit older). Sigma still sells a 70-200 zoom for a reasonable price (cheaper than Canon's f/4 L zoom, but about the same as Nikon's 80-200 zoom).Sigma 10-20, Tamron 28-75, Canon 50mm II, Tamron 90mm Macro. I want to sell my macro lens and buy a 70-200, but I won't pay the premium for f/2.8 and f/4 is a stop too slow for me.
I'm still old-school, i. e. IMO nothing can replace a larger aperture (great for portraits and close-ups). With dslrs, speed is not that much of a factor anymore, I got really used to a 2.8 f-stop a few years ago on my first 28-70 (Tokina) zoom which gave me so many more options to take pictures.