Confusion over BTC value - MtGox vs CoinDesk I'm trying to find the current value of BTC.

If I go to MtGox the ticker at the top says the average price is about $950 but at CoinDesk.com the daily high, low etc are all $100 cheaper...

Both are in USD.

The CoinDesk seems to be the accurate one but why are the MtGox values so much higher?
MtGox is an exchange: people trade Bitcoin for USD there. The value they report is what the exchange rate is on MtGox.

CoinDesk calculates its Bitcoin Price Index based on a number of factors, including MtGox's price, and the prices on other exchanges. This appears to be a much better indicator of the true market value than MtGox's exchange rate.

You might wonder, if the price difference is so large, why don't people buy on one and sell on the other to make a profit? People do, in something called arbitrage trading, but how close this will bring the markets depends on the overall costs of the transactions (fees, etc.). Since getting USD out of MtGox is not easy (or even possible?) at the moment, the gap can be quite large.