Obviously, I have a lot to say on the topic, but here are the three big ones that I'd like to touch on briefly.
Myth # 1
You have to completely clear your mind of all thoughts to meditate
This isn't true, meditation is learning the ability to train and focus your thoughts on a fixed object.
Myth # 2
You have to be seated cross legged on the floor in order to meditate
Actually, you can meditate while walking, running, lying down or sitting in a chair.
Myth # 3
You have to practice yoga to meditate
Yoga is an excellent preparation for meditation. And you can meditate and practice yoga, but they are not synonymous. Meditation can be a practice completely of its own. You can do both or pick one that suits you, your lifestyle, goals and personality.