I have seen a lot of Bitcoin exchanges, BTC-e, Coinbase, Bitstamp, LocalBitcoins and Bitfinex. (I saw those on blockchain.info) But which one of them is the real bitcoin value?
There is no such thing as a the "real" value.
The value of Bitcoin as denoted in another currency (USD, EUR, etc...) is based on how many people are buying and selling, and in what quantities. On different exchanges, there are different numbers of people buying and selling different amounts of bitcoin. Each exchange calculates its current posted value based on the quantity and amount of the bid and ask orders currently on the exchange. The results will be different from exchange to exchange, because people are buying and selling differently on these exchanges.
All exchanges provide the real value, relative to the trades on their exchange. The value of a Bitcoin can be different on different exchanges because people are buying at different rates. It's the last price a Bitcoin sold for that determines the value of the coin on the exchange.