Think he's asking about ixcoin (the money-grabbing fork with pre-mined coins) and you're answering about bitcoin.
The calculations for block generation with a given difficulty work exactly the same for bitcoin or anything else using the bitcoin sha256(sha256(input)) algorithm. But the math is dead wrong.
At current 16k difficulty, 1 Ghash/sec generates a block every 19 hours and 32 minutes, on average. As for why to mine IXcoins, someone bought the market up about 500% a couple of days ago, with an investment of several hundred BTC, so there's still interest. My guess is when difficulty drops back to 4k and people rush in, the value of IXcoins will shoot back up above the BTC equivalent, given the difficulty/output ratios.