Choosing a broker can be quite tricky. With the rise in popularity of online forex trading, brokers do everything they can to differentiate themselves from their competitors. This means spewing a bunch of terms such as Non-Dealing Desk (NDD), Straight Through Processing (STP), Electronic Communications Network (ECN), and you get the point. However, these buzz words are essentially meaningless on the retail level. There is absolutely no way of knowing how these brokers operate.
There is really only a handful of brokers that are in the business long enough to be trusted. A quick rule of thumb is any broker in Malta, Cyprus, or the British Virgin Islands should be avoided. Their regulations are meaningless and brokers pop up faster than regulators can shut them down. For any serious traders depositing significant sums, stick with NFA/CFTC, FSA, and ASIC regulated brokers.
Head over to the my brokers page for a list of recommendations. These brokers have an extensive operating history and deemed more trustworthy than the bucket shops rapidly popping up.