I want to buy a second camera for when the DSLR is inappropriate?

So, I use a Nikon D4 which I love. But, recently while I was out and about… Someone tried to steal it. Of course, nothing happened… But, this has scared me a bit. I was in London.

I'm not going to stop using my D4… That would defeat the purpose of buying it. But, I do want a camera that I can use when I'm walking about and just blend in to the crowd… Instead of walking about with the camera equivalent of a machine gun.

I was thinking to go for either one of the Fuji x100t/s or the xt-1 (probably with the 18 or 27mm lens).

The main criteria are user-friendliness, speed, image quality and build quality.
Any ideas? Any other suggestions?

feel free to check out some of my more recent "work". https://500px.com/...rmapmukesh

Added (1). in response to fhotoace… User friendly was probably the wrong term… Basically, it needs to be slr like in terms of controls (individual customisable controls instead of one button for everything.)

If you buy another Nikon digital SLR, like the D610, you can use the same lenses you have now, but it is much smaller and not as conspicuous.

If you have the budget then the new Fujifilm X series cameras are excellent,

DXOmark has yet to test any of the Fujifilm X camera, so you can't compare the sensor performance with the Nikon D4 and D610, but you can compare their specifications

NOTE: If you understand how to use your Nikon D4, you do not need " user-friendliness" All cameras work the same… You just need to use the cameras lightmeter and use your skills balancing ISO, shutter speed and lens aperture

If you are looking for something significantly smaller, get a Sony Cybershot (about $200 or more would be best). You will end up severely wanting in the controls department though so my next recommendation would be a Fujifilm X-Pro (or something close to that).

The camera for you is the Fujifilm S4800. Not only does it have 30x optical zoom, but it has aperture and shutter priority modes. It shoots HD video. And it does have a viewfinder. And you can probably get it for around $150.

I think the perfect camera would be the Sony A7 series. They are small and inconspicuous. Not only can they can be adapted to accept all of your current Nikkor glass, but also all of the lenses from Canon (they just announced the new EF 11mm-24mm), Leica M or R, or any other lens ever made for the 35mm format.
Sony makes three versions of the A7: The A7S is 12MP and designed for people who don't need higher pixel count, but instead need the best high-ISO performance on the market.
The A7R has the same 36MP sensor as the Nikon D800 and is designed for those not needing to shoot at high ISOs such as landscape, studio work, etc…
The A7 is a happy medium with it's 24MP.