IMHO, the biggest opportunity for scamming is the large scale DDoS attacks on the exchanges we've been seeing lately. I believe these to be orchestrated events by organized groups with access to large resources and are using BTC as a pure speculative market. Think of organized crime and investment banks. They engage in the DDoS attacks in an effort to manipulate the market and get their orders executed. I would imagine the savvy algorithmic traders and hedge funds are engaged in these practices as well.
The way to stop it is for the BTC network to get even more distributed and even more liquid (needs to be used for more transactions and not simply as a store of fiat currency value, but a value store in and of itself)
Agreed. These are not some random attacks they are trying to manipulate the value of bitcoin and it worked (for now). some seem to have dumped their bitcoins for record low amounts and then the value was reinflated.
Most actors (aka pool operators and exchanges) have taken measures to minimize the impact of future ddos.
What you as a private person need to do is to take as much care if not more as when doing online banking. If you have an account make sure it has a strong password. Encrypt you wallet.dat take backups (remember the wallet is your physical notes) Someone can easily break in to you unsecured computer.