Neumann 140 /184. I have never really been able to tell the difference between the two in sound quality.
Perhaps I'm wrong but I thought the KM14x and the 18x are the same mics, other than the 14x's have interchangeable caps and the 18x's have fixed caps (?)
I'm not sure I could ever reasonably answer this question - so many different mic configurations and placements, pre's, etc. that I've rarely been able to compare two sets of mics in an apples and apples situation. There's been a few times where we've run two sets of mics in the same spot and pattern and relatively similar gear that led me to like the sound of one over the other, but that could be specific to the venue and/or location and in a similar test in a different location or venue I might like them the other way around. Try asking the same question about favorite pre-amp and you'll get a similar diversified response...kind of like asking the best flavor of ice cream.
Back in the GD FOB days, I always thought the Senn 421s really shined...I've never had a chance to try those out in more current taping situations to see how they do. Makes me wonder what happened to all of the 421s and 441s that used to be around - I never see or hear of them anymore. I do think that AKG recordings that get made for me always seem to impress me - again, I can't compare them to what other mics would have sounded like in the same venue and pattern, but from a subjective standpoint, they always seem to sound pretty good to my ears. As for the KM140s, of course I'm biased, but when I nail a recording with them, I find them hard to beat for that full, warm sound they are capable of.