I've developed a bit of an addiction to street photography since moving to Tasmania and the X30 is perfect for the style I do. Many deride the smaller sensor but for street photography it's great as you get more depth of field without having to bump the aperture up to F8. The almost silent shutter helps a lot too as on a noisy street you can't hear it at all, unlike my friend's X-Pro 1 which you can definitely hear. The fast burst mode is great too and helps to ensure you'll get a few options.
The X40 can't be far away and I'm excited to see what they do with it, whether it will be another big change or a more gradual upgrade. My main wish list would be better high ISO performance, not necessarily a larger sensor although the 1" would still give decent depth of field. Time will tell....
Here's a link to a blog post I put up recently on the experience of shooting street photography with the X30.
https://czechingoutofhere.wordpress.com/2015/09/17/street-photography-with-the-fujifilm-x30/