Are Kali Linux or BackTrack distros to go if I want to learn hacking, or is it better to install only the tools I want to another distro? I've already used Kali in the past but I didn't like it very much. I've read somewhere that the tools are hard to install, so is it better to have one of the distros? And if so, which one?
I suggest to use some wellknown distribution, for example debian. But really not the distrib which is important.
The main problem is that hacking is an interdisciplinary thing. You can't really good learn directly hacking, it weren't really efficient. If you want to do things efficiently, you need to learn things which don't have to do with hacking directly.
As a first thing, set up your own server and try to make that secure.
Next to that, look for well known security holes on the net. (How? Where? It is another important saga.)
The default install of your distribution probably fixed them. Look, what was really the bug, and how was it fixed. Then try to re-open that on your system, and test if it works. Then close again. http://security.stackexchange.com were a good site for this if you want to get support.
It will be much better if you could do such problematic things on a sandbox, which could be a virtualized server on your host. Deep system administration knowledge, especially around virtualization, will be an important thing for anyway.
Until then, you will have to learn linux/unix deeply (very deeply! You will smile to see this actual post about finding distros...), and C deeply as well. http://serverfault.com and http://superuser.com can be good support sites for you.
If you want to do things hard, it will take at least years, if you have a hacker/programmer/linuxer brain. If you not, you don't have any chance.
If you do things until a half year relatively hardly, I think, you will learn enough to know, in which direction you need to go further. From that point, things will depend only on your curiosity.
On the longterm I must mention: probably you won't earn too high wages with that. If you fill this some more... worthly IT knowledge (programming frameworks on current languages), you will get out finally much better.
If you can, it is very good if you start at least a IT-related BSc course on a regional education institute (university). First, you will be able to learn things which can't be learned from the internet. Second, you will be able to get wellpaid jobs with that, where you will find also very good ways to learn, on the defensive side.