Much of the world considers the thumbs up to have the same meaning, that of positivity; however, there are quite a few countries that consider it to be of the most obscene gestures possible. In most Middle Eastern countries, the gesture translates as the foulest of all gesticular insults, literally translating to "Up Yours!" The same can be said in parts of West Africa, South America and even Sardinia. One particularly interesting note is that while the country of Iran finds the gesture reprehensible(equalling the middle finger), the neighboring country of Iraq uses it in its traditional positive meaning. On that note, if you find yourself back-packing through Iran, don't try to hitchhike.
In general, this gesture is a positive response, meaning something is acceptable, or "okay." However even in America this can have a negative connotation. Specifically, in American sign language, this same gesture held with the back of the hand parallel to the ground means "asshole." Similarly, in countries such as Venezuela, Turkey, this sign again is connotated negatively, generally referring to homosexuality. In Brazil, the gesture means essentially the same this as the middle finger also.
Depending mainly on how the sign is held and delivered, the V sign can mean quite a few things. Traditionally, with the index, and middle fingers raised and the palm facing outward, the sign means "peace," and is widely used around the world. Turn the hand around, with the back facing out, and the V becomes quite insulting in many parts of the world. Seeming to originate in England, and still used there to this day, the V sign is generally found within areas heavily influenced by the British. Countries such as Ireland, New Zealand, and Austrailia, and even South Africa use the sign as their version of the middle finger.
The fig sign is a gesture where the hand is in a fist with the thumb poking out between the index and middle fingers. It's either a good luck charm or the worst insult you could ever give someone, it all depends on where you happen to be at the time. In ancient Rome, an image of a hand in the fig sign was worn as an amulet to protect against evil. In places like Indonesia, China, Russia, and some Mediterranean regions (particularly Turkey), the sign can have a meaning roughly equivalent to "screw you."
Best known as a heavy metal headbanger concert sign that became popular in the late '60s, the devil horns origins stretch back much further. The sign of the horns, was an ancient European guard against evil, much like the fig sign. However, in Mediterranean countries, particularly Italy, and in Cuba, you'll see the devil horns flashed often on the road, where irate drivers express to each other that their wife is, let's just say, of loose morals.