Future Kyle says: The answer was BOTH, as is so often the case.Right now the 23 is battling the 18-55 as the lens I need the most. Most of the time, when I find myself wishing I had the 18-55, it's because I own nothing between the 14 and the 35 (except the 27, which is usually too long and very often too slow, but IS delightfully tiny). The zoom would just stay glued to the camera most of the time (he tells himself), whereas the 23 would push me towards having 2 bodies -- ideally an XE2.
I honestly don't know which I'd spring for if I were buying right now. Logic says the zoom, but my tendency to shoot in the dark / my love of the 23 FOV says the 23.