I've had my XE-1 for about a year now and love the camera - it's really gotten me into photography. I started out with the 18-55 kit lens, then added the 35mm 1.4 a few months later. While the kit lens is great, I LOVE the way pictures turn out from the 35mm. I think partially its the prime forcing me to better compose my shot, but also there's something special about this lens.
I'd like to expand my kit, but am having trouble deciding which way to go. My initial thought was to go with the 14mm, because of the small size and the ability to increase my focal length range into wide angle. I like taking architectural and landscape shots on vacations, and have felt limited sometimes by the 18mm on the kit. I also really like shooting at night though, and the extra stops on the 35mm have been helpful for a non-stabilized lens - so enter the 16mm.
The more reviews I read about the 16mm, it seems like a really amazing lens. I'd get the extra focal length, but could potentially use it for more situations. Both to shoot street at night and to shoot people indoors, without the fear of distortion that I might get with the 14mm.
On the other hand, when I look at what I use generally walking around when not on vacation, I tend to shoot at either 23mm or 35mm on the zoom. Which leads me to wonder if getting the 23mm or a used X100s might make most sense. It would provide more enjoyment when I'm not traveling, but wouldn't necessarily expand my range of available focal lengths.
Sorry for the rambling post - at the end of the day, I think the ranking of characteristics are 1) lens I love using - the 35mm has a really special quality and 2) expand my focal length range. Appreciate everyone's thoughts and experiences!
Here's a link to give an idea of what I like to shoot: 500px.com/wdshuck