I have not used a DSLR in last 3 years and I am in not condition to give you suggestions about what camera to buy. But as you already mentioned you want to shoot ocassional family, landscapes and night photography, you should base your decision in what is most important to you.

If you want to shoot mostly family pictures and as you said you are not a pro photographer, why don't you instead stick to your own gear for now, and invest on lens instead. If you are really into portraits of your family, why don't you buy a lens that suits for it, for eg. Nikon 85 mm (f1.8 or f1.4 g) or even cheaper option Nikon 50 (f1.8). If you are really into landscapes, why not some wide angle lens? lets say, 10-20mm. Also, why not invest some of money to buy flashlights as the other guys suggested above, try using off camera flashes in your portraits and try all new world of strobist (strobist.blogspot.com/)? 

If you are really into buying a pro level camera and you think that would change your results drastically, think about accesories you have now (for eg., flashes, remotes, lenses). If you are using nikon now and want to switch to canon, those will be worthless to you, so you will either have to sell them cheap on ebay or throw them out of window. 

I am suggesting you to invest more on lenses and flash, because, then you will find out more about photography in general, and those accesories will be usable, if you want to upgrade your gear later on. You will just have to buy a camera body, and voila, you will have all the accesories you need to show your magic on that new camera.

Best of luck in whatever you do, and enjoy taking pictures.