Still have yet to find a block myself since the ASIC revolution, and I'm hashing 5 THash. Back when I was hashing 3 or so GHash on GPUs, I wound up discovering 11 blocks as part of a pool. It is luck and risk really. I look back and do the math thinking I could have earned 550 BTC at that time, but reality due to pool mining is I earned half that. I miss the days of pulling in 10 BTC a week...