How many ways are there to lay out tarot cards, and which is the best?
It's unlimited. There are dozens of spreads that have been created and written about in books, and there is nothing to stop you from creating your own... as many as you want.
There is no such thing as "the best" spread. There are only different spreads for different purposes, depending on the issue at hand, the level of detail you want, and your comfort level with interpreting spreads at those levels of detail.
Probably one of the most popular spreads, and one that is pretty easy for beginners, has been called the "Celtic Cross," but even with this one spread, there are different ways of interpreting the layout. Here are a few. The first one is the version I first learned more than 15 years ago:
The only place to lay them is in the fire. Turn or burn! To dable with the Devil is a Evil-Death.
There are many hundreds of layouts to choose from.
I feel that the best spreads are those that you make for yourself.
There are as many ways as you can think of, and for every one way you can think of there are 10 ways that you have not thought of.
I lay my cards out different all the time. It depends on the question and my mood.
What is best? What feels right.