Most of the numbers floating around the internet and nearly every mainstream news piece about bitcoin's energy consumption are wrong. They cite an outdated statistic maintained by blockchain.info that assumed everyone was using a GPU even when nearly all of the network was ASICs.
I would estimate the current network (25Ph/s) averages around 2-5W per Gh/s, leading to 50-125MW total power use. bbosh in this thread is off by an order of magnitude.
I haven't cited any statistic from blockchain.info, and haven't considered hardware at all. All I have done is employ economic argument, which I think makes sense. It doesn't matter whether or not particular individuals are using ASICs. All that matters is that, collectively, they are making only a tiny profit (if any). This argument doesn't require consideration of hash-rate or particular hardware at all.
I would estimate the current network (25Ph/s) averages around 2-5W per Gh/s, leading to 50-125MW total power use. bbosh in this thread is off by an order of magnitude.