It's very difficult to get together a list of unscrupulous apps in the App Store because any behind-the-scenes naughtywork has to be pretty well hidden to keep the chance of Apple detecting it as low as possible. A lot of these lists are merely accusations, but very few actually have any evidence of a program having anything hidden in them. Usually Apple does a good job of removing these after someone posts a credible claim online.
As for how your account was hacked, it could be tied to a recent string of hacked accounts. Some evil developers got a hold of a list of iTunes accounts and passwords (as far as I know, there hasn't been any revelation as to where this list came from, although there are a lot of theories, from hacking Apple's servers to keyloggers and phishing). These developers then used these passwords to purchase hundreds of dollars worth of their own apps using their victims' accounts.
Here is a list of some articles regarding the scandal:
Reports: iTunes accounts, App Store hacked | Apple - CNET News
App Store, Hacked. (Updated: iTunes Accounts too.)
App Store Hacked… Again!
App Store, Hacked? [Update: Apple has removed fraudulent developer from App Store]
iTunes Hackers Raid Accounts, Charge Untold Amounts - The Consumerist
Check your purchase history to see if the stolen money was spent on apps by a small number of developers. Print all purchase histories that contain purchases you did not make, and forward this and any other information you find to law enforcement and Apple. Let them know about these articles I linked to as well. Also, I suggest emailing Steve Jobs directly. I've never done it, but a lot of people actually get a reply from Steve himself. People email him with problems that Customer Service refuses to handle, and in some cases get their problem resolved very quickly. Remember that Apple has to compete with brands like Microsoft that have huge head-starts on numbers of customers, so they try to keep up their reputation for customer service sometimes at surprising lengths. I found the following two email addresses that reportedly go straight to CEO Steve Jobs: sjobs@apple.com and Steve@Apple.com (the first one seems to have the most people vouching for it).
Good luck, and I hope you get your money back! And if you haven't already, change your iTunes password!
