Is it better to be single or in a relationship?

I'm 27 years old and I've been steadily dating different girls. It never really leads to anything serious but a lot of my friends who have been settling down, getting married and having kids think that I should be in a relationship with somebody. I'm kind of torn. It would be nice if I had somebody but I kind of like being single. At my age, should I be looking to settle down or should I keep doing what I'm doing.