Efficient Markets?
I don't think so. The theory/hypothesis is full of crap. We learned this in our finance classes in our MBA, but I don't buy it. There are several versions of it, but even the most weak of the arguments claims that technical analysis won't work. From what I've studied of technical analysis, it's trying to use numbers and history to predict aggregate investor psychology. A simple form would be that if a stock is at it's 52 week high, more investors think it's time to take profits than investors think it's time to get into the stock, so the price will probably go down.
Efficient theory claims the market is a machine that absorbs information and adjusts the prices within seconds to account for that information. Nothing else matters. I think the market is made up of people, and people have feelings, and stocks become either overhyped or forgotten. And when that stock hits it's 52 week high, I know I start to consider taking my money off the table...
I like Warren Buffett's feeling on the matter (which comes from Benjamin Graham). Take a look at this commentary also.