[zargon]

If you paid cash for the cash you received in the mail, it wouldn't be income either, would it? (though it makes little sense.)

Most people earning income in bitcoin probably aren't doing it by mining, especially after ASIC arrives. Just to point out that mining is only one of many ways to earn bitcoin income.

[yebyen]

Right, there's also arbitrage trading on markets which have fluctuating market rates, plus regular buying and selling over longer periods of times, transaction fees (both from mining and from trading), and simply accepting Bitcoin as payment for services.

I am not so sure that ASIC will kill the small-time mining scene, the low-end ASIC miners are cheaper and less power hungry than video cards (though you can't play games on them), it will just mean that if you want to mine bitcoins, you'll have to get one (or more), and you can't rely on your video card anymore. So a lot of people will be pushed out.