There's no single clone that's better than all the rest. There's pros and cons for each and every type. So don't think that you can stick to just a few awesome types and not waste time on the others. It's not really like that. Just get hold of a nice variety of different clones and you will learn from and appreciate each one in it's own special ways. Even common old PC is good for some things, especially if you get a ute load for free.
Having said all that there are a few all round tried and true standouts that will always satisfy your cactus growing interest. 1 in particular is Psycho0. It's just a great performer that deserves a place in any cacti collection.
However, this list of recommendations will quickly explode to include almost every clone there is.