Is there one right religion?
A simple question, and like all simple questions extremely difficult to answer. To me the short answer is "no", but then that warrants a long answer doesn't it.
To answer this question on must ask questions. For instance what does "right" mean? What are the differences in the religions of the world? Is western religion right or is eastern? If out in the octagon will Vishnu knock out Yahweh or could Jesus submit Buddha with a triangle choke?
In my opinion the problem with religion and finding one "right one" is in the phrasing "one." Rather exclusionary don't you think. Look at the 3 major religions of the west. Each believe that they are right and are so focused on that fact that they ignore hundreds of similarities. Not to say this isn't true of eastern religion. Hinduism begets Buddhism and Jainism. Buddhism has many subdivisions depending on the region and let's not forget also Taoism and Shinto.
Each of these religions has great ideas and principles. They all encourage tolerance, forgiveness and love. Each tries to help put a persons place in the universe into perspective. So really what it comes down to (and you knew it would) is personal choice, because all of these religions are right so therefore there is no "one" that is "right."
For my money I like Zoroastrianism. Most of the foundations of western and eastern religion can be found there. What I really like is there non judgmental streak, since they believe that all forms of worship are directed (knowingly or not) to their god. Also their is Agnosticism, which I think is a growing movement in the world today. There are ranges in it as there are anything. The basic tenant as I understand it is that no one can truly know if there is or isn't a God in the universe. Some lean more to not knowing but believing that there is a greater being, others to not believing but not discounting. I believe that there is a greater being in the universe, but try not to label or box that belief into any particular system.
Perhaps the best wisdom on religion can be found in pop culture. In Dogma Kevin Smith said that one of the major problems of the world is that people take a good idea and make a belief system out of it. So if you need to have one good religion be a student and believer in the fundamental ideas of all religions. That way you have all your bases covered.