There are many stereotypes surrounding Chihuahuas, none of which are very flattering. When many people think of Chihuahuas they think of noisy, mean little ankle biters. But putting any kind of label on any breed of dog is unjustified. Yes, there may be some Chihuahuas that are full of attitude and mighty barks, but they are the minority.
My experience with Chihuahuas show them as loving, people oriented dogs that don't bark any more than any other dog (and many have been very quiet individuals).
Chihuahuas and pit bulls make up 70% of animals in shelters right now, and it's prejudices like the ones mentioned here that are partly to blame. The other, bigger cause of this statistic is over breeding. People believe they can make money breeding cute little puppies (while the same cute little puppies are being euthanized in shelters across the U.S), and when they are unable to sell these puppies they get abandoned. It's a vicious circle.
If you're looking for a great pet, check out one of the many Chihuahuas sitting at your local shelters and rescues, you'll surely find one perfect for you!