There are many types of yoga, some with more emphasis on the physical part of the practice and some with a more spiritual approach, some that will make you sweat and some where you'd spend half a class holding the same posture.
There is a type of yoga for anyone!
When choosing a class that's right for you, you have to consider your personal preferences. It's perfectly normal to try out a few yoga methods, until you find the system that you feel the most comfortable with.
Ashtanga is a very physically challenging practice, that is based on ethical principles.
Hatha yoga is a classical practice that is a little slower-paced, with more emphasis on held postures. It is well suited for seniors or for people who'd like a more relaxed class, with an emphasis on flexibility.
The popular Sivananda yoga system is derived from the classical hatha.
Iyengar yoga stresses precision and uses a lot of props in class. It's excellent for people with injuries.
Bikram is hatha yoga, practiced in a heated room. Every Bikram class features the same sequence of poses (every pose held twice) and doesn't include chanting om, which probably won't be the most satisfying experience for those who are spiritually inclined. Excellent, if you love to sweat!
Vinyasa yoga class consists of multiple poses, connected by breath. This type of a flowing class is very energizing and physically challenging, so A-type personalities would probably find it the most attractive. The now popular OM and Jivamukti yoga methods feature a hatha-based vinyasa.
Anastasia Dorohova is a fully certified and registered yoga teacher, teaching private and corporate vinyasa yoga classes in New York. http://www.steadybliss.com for more