This is going to be a very broad answer for a very broad question.
What's the best camera?
There really is no best since the tech is always evolving. So is there a best right now? Short answer yes, but it depends on the criteria you judge by as to which camera will come to on top so lets make it more simple.
Figure out what type of photography you want to do. Then look into what type of equipment is required i.e. long focal length, studio lighting etc. Then go and try out the camera bodies that are in your price range. If you have questions about these models that you've narrowed it down to, you will get more accurate answers since I'll bet at least one member here has owned one.
Now for the Nikon/Canon debate. Each make cameras that can capture amazing images so it mostly comes down to what you like or what lenses are available.
Now that I've not really answered your question. I'll answer the one you haven't asked.
Will I be able to take great photos with (insert make model here) camera? Well, yes. If you are willing to learn the basics of whatever type of photography that you are interested in, you can take some great shots. The photographer takes a great picture. The camera only records it.
Oh and welcome to TPF.
P.S. I'm still a noob so take all of the above with a grain of freshly mined salt.