Meditation is part and parcel of yoga as a discipline. If a studio is not teaching that aspect, I would question their legtimacy. There are many, many, many weekend yoga teacher trainings out there and they are about as useful as the weekend personal trainer certs.
There are good reasons to have a class sit for a few minutes prior to starting--mostly because it will focus you and settle you down.
As far as yoga styles, a few common ones are:
Bikram--ok, but often taught by people who have never done anything else and don't know anything about yoga other than what Bikram teaches. Persoanlly I hate it and it makes my back hurt.
Hatha--probably the most common form of yoga in the states. Certainly has been around the longest.
Power Yoga--- While Bikram is a brand name and a style of yoga, "Power Yoga" can refer to many different styles. Most of these schools will often teach Ashtanga yoga, which is a more vigorous practice than Hatha. Most Ashtanga places I've been to incorporate vinyasa (flow) at least to some degree. Some, like Baron Baptiste's schools, combine Ashtanga poses, flowing between poses, and practice in a very hot room.
I think this is the best style for athletes, particularly for grapplers. It is also a hell of a workout.
Kripalu yoga--a vinyasa practice, much gentler than Baptistes, but also largely based in Ashtanga. I go to the Kripalu Center in Lenox MA 2-3 times a year for at least a few days at a time.
PS--these are only the styles I've done---there are many others. One to avoid at ALL COST is Dahn Yoga--I suspect they are run by the same people who run the Chung Moo Do/Chung Mu Kwan cult-style TMA schools. Their practice is an amalgamation of chi gung, yoga, and some shit they seem to have made up on their own.