I think that virtue (character) is important. One way of illustrating this is in the following "rework" of a line from Martin Luther King Jr.'s "I have a dream" speech.
I have a dream that [people] will one day live in a nation where they will not be judged by [what they own, their accomplishments, or their physical abilities] but by the content of their character.
If you we look to the well-being as a matter of satisfying our desires or being successful in our life, then virtue is not an essential part of well-being. It is possible to have well-being (in this sense) without virtue. And as @Amir said Trump is a good example.
Yes, I agree with Aristotle's belief that being a virtuous person was essential to one's life going well. Being virtuous, i.e. behaving in a very honest and moral way, is important for being a reliable person and thus making one's life going well.
The view of McCullough & Snyder (2000) is that the character is a higher-order construct reflecting the possession of several of the component virtues. According to Opatha (2010) absence of virtues results in the absence of a good personal character. Possession of virtues contributes to a good personal character, which leads to good personal quality. Good qualities or habits which do not harm a person are virtues. These are advantageous and favorable for self-development, others’ development and institutional development.
Zagzebski (1998) presents a set of virtues. They are namely, Wisdom, Courage, Benevolence, Justice, Honesty, Loyalty, Integrity and Generosity. Opatha & Teong (2014) are also present a set of virtues. They are, Honesty, Patience, Gratitude, Humility, Respect, Benevolence, Tolerance, Self-Discipline, Caring, Loyalty.
References
McCullough, M.E. & Snyder, C. R. (2000), Classical Sources of Human Strength: Revisiting an Old Home and Building a New One, Journal of Social and Clinical Psychology, 19, 1–10.
Opatha, H.H.D.N.P (2010), Personal Quality, University of Sri Jayewardenepura.
Zagzebski, L.T. (1998), Virtues of the Mind, Cambridge University Press.
Opatha, H. H.D.N.P., & Teong, L. K., 2014. Enhancing your personal Q. Sintok; Universiti Utara Malaysia, UUM Press.
Being virtuous, or at least, consistently trying to "do the right thing," is what lets you sleep well at night. So to speak. I'm convinced that those who don't follow this path end up with some deep-seated self-loathing problems, long term.
We are social creatures. If nothing else, even the most callous of dishonest, selfish, and inconsiderate people cannot help but notice that he/she is despised by those around them? I don't see how that can be a good thing for anyone.
If I agree, since generally the virtuous person thinks and acts in consequence, he creates a positive (virtuous) environment around him, be it family, friendships or social groups; opposite situation when people are cruel, dishonest or unprofitable.