The sound of the nylon string acoustic guitar is softer and smoother than the sound of the steel string acoustic guitar. Strangely, the depth of feeling in a nylon string guitar still has the power to enchant people today. It's up to you to decide which one to play. I could name a bunch of artists who used either nylon or steel string for this or that record and make some wild guesses about why they did what they did, but the bottom line is that the nylon string guitar is the way to go if you want a deep, quiet sound that doesn't compete with your voice.
When you go out to buy a guitar, skip the general music store and go to your local guitar dealer, if you have one. So, you'll be led by a guitar pro instead of some idiot who can only play two-and-a-half chords. Don't let the guy in the store push you toward the most expensive guitars, and don't give in to your inner cheapskate, either. Choose a guitar that you like in terms of how it looks, sounds, and feels, and if you have to, go cheaper.
The Alvarez Masterworks Series MC90 Classical Guitar, which costs over $600, has solid rosewood back and sides, a western cedar top with precision scalloped bracing, a mosaic rosette, gold tuning pegs with tortoise buttons, and scalloped bracing on the top. The Alvarez Regent, which is good for beginners, costs around $150. There are, of course, many prices and levels of quality in between.
The nylon string guitar was made for classical and flamenco music. Classical guitar music is classical music written for other instruments but arranged to be played on the guitar. It also includes pieces written in the classical style that were written for the guitar or other stringed instruments. There is a lot of music from the Middle Ages and Renaissance that was written for the vihuela or mandolin and then arranged for the guitar. This music can be very fun and satisfying to play. Flamenco is a type of folk music from Spain. Because flamenco is a "flashy" style of music, it is often very technically advanced. If you want to learn more about either of these kinds of music, you should go to YouTube and look for videos of classical guitar or flamenco guitar. Classical guitar fans should start with John Williams (the British guitarist, not the Star Wars guy) and Julian Bream. Flamenco will win your heart over if you listen to Paco De Lucia, Paco Pena, or Sabicas.
We can't end without talking about the folk music boom of the 1960s, which was driven by the nylon string guitar. This gave us a lot of great music that is easy for new guitarists to learn. Guitarists today are still interested in the music of Pete Seeger, Burl Ives, Joan Baez, and The Kingston Trio.
So, that's an overview of the world of the nylon string guitar. I hope you found something that interested you.