Welcome to the forum!
You'll get lots of opinions about the "best" track, rolling stock (cars), and engines. Everyone has his or her favorites. And "best" may not necessarily be the same as "easiest to work with."
In the "easiest to work with" category, many people will recommend Kato Unitrack. Unitrack is a type of sectional track, with straight, curved, and turnout pieces of various sizes the snap together easily and require little in the way of specialized tools or skills to assemble. You can buy Unitrack starter sets that include enough track to make a simple oval or an oval with a passing siding. You can later buy expansion sets to add more track features or even buy individual Unitrack pieces to expand your layout with your own ideas.
While Unitrack probably wins the "easiest to work with" category and is basically foolproof, some modelers feel it is not sufficiently realistic. So in that sense, Unitrack may not be the "best," although some wonderful model railroads have been made with Unitrack. But you begin to see how differences of opinion can enter the discussion. Unitrack is among the more expensive track systems as well.
Other manufacturers also make sectional track, and they all have their pros and cons. Beyond that, there is so-called flex track, where you purchase long pieces of track which you then cut and bend to form the track plan of your choice. Flex track is generally more realistic than sectional track. But where it might take you an afternoon to lay the track for a simple Unitrack layout, it might take a week to do the same thing with flex track, even assuming you had the necessary tools and knowledge. Whether a more realistic final result is more important than a quick and easy project is an individual decision.
All of this is a gross over-simplification of a hobby where you can spend a lifetime and still not know all there is to know.
I'm certainly not trying to sell you on Kato Unitrack. I don't use it myself. If getting trains running quickly and easily is one of your top requirements, it's probably a good choice. If maximum realism is a key requirement, there may be better choices. Kato also sells train sets and individual cars and engines, and they are considered to be of very good quality. However, with rare exceptions, any N-scale manufacturer's cars and engines will work with any manufacturer's N-scale track.
Here is the Kato web site:
http://www.katousa.com/
I'm sure others will add their recommendations!
- Jeff