This thread has been interesting to follow. I don't think I've ever been especially conflicted about deciding between multiple lenses. Usually I'm either looking for something very specific - like a DA Ltd or a long telephoto - or there is such a cost differential between two competing lenses that the price dictates the sale (my used DA 17-70/4 was one-third the price of a used DA 16-85). Probably the closest I ever came to making a "hard decision" between two lenses was last year choosing between the Sigma 10-20/3.5 and Pentax DA 12-24, and even that wasn't too tough because I really like the rendering of my Pentax glass.
So, deciding
I want a new lens and then having to choose between three significantly different models is pretty interesting.
Edit: Oh wait! Last year I
did agonize for a while between the A* 600/5.6 and the K 500/4.5. At that time I had the discretionary funding to drop $2k on the A* and was seriously tempted, versus my more frugal nature leading me toward the K 500. Frugality won the day, and given what's happening right now that turned out to be a fortuitous decision.