I have said before that it doesn't matter as much what Camera you use but how you use it. Having said that I need to say that I have a strong opinion about a few must haves in most camera bags.
The first one being a fast 50mm lens. You can pick a 50mm f/1.8 up at most camera stores for around $100. The 50 is a "prime" lens meaning it is a fixed focal length and does not zoom. Canon has three different 50mm lenses, the f/1.8, f/1.4 and the f/1.2. The range in price from around $100 for the 1.8 to about $1,200 for the 1.2. the difference between the three lenses boils down to build quality, depth of field/aperture size and sharpness.
The next two must haves are fixed aperture zooms. I have the 24-70mm f/2.8 and the 70-200 f/2.8. With a fixed aperture lens I am able to shoot at f/2.8 from 24mm to 200mm. With kit lenses or other cheaper lenses when you zoom from 24 to 200mm your aperture will automatically change. you might start off at f/3.5 at 24mm but when you zoom all the way out to 200mm your largest aperture will only be around f/5.6. The difference between me shooting at f2.8 zoomed out to 200mm and you shooting at 5.6 at the same focal length is huge. My background for a portrait will be way more out of focus and I will be able to shoot at a faster shutter speed at a lower ISO. Another aspect of the fixed aperture zooms is that they generally have a better build quality and are sharper.
Whenever I purchase a new camera I always make sure I also have a way to trigger it remotely. The camera I am using now can be triggered with a cable release or a wireless remote. You might be asking why this is on my list. I have it on here because if you don't have a way to keep your camera's shutter open for longer then 30 seconds you are missing out on a whole feature that SLR cameras have, the Bulb setting. with your camera in bulb mode as long as the shutter button is held down your shutter will stay open. Doing this at night can result in some very interesting images. Another advantage of the remotes are that when you are shooting at slower shutter speeds you don't need to touch the camera and possibly shake it resulting in a blurry image.
I can't stress this enough. Lens cloths, have several good quality lens cloths. A clean camera or lens is a happy camera or lens.
last of all, get yourself a good quality sturdy tripod. If you hike a lot get a light one but make sure it is stable and can support your camera's weight. I just bought new head for my tripod because the old one kept slipping and was causing some of my long exposure night shots to come out blurred because the camera was gradually moving during the exposure.
If you have any further questions regarding gear leave a comment below. This list of items is not exhaustive and there are more things I would put on here but I will save them for another time.