I’m an owner of Nik’s very nice Silver Efex Pro and Color Efex Pro. They were acquired by Google, which I thought was bad news, and luckily I have so far been proved wrong.
They just announced a price drop of the complete collection, to $149 from $499. That’s a stellar price, and less than I paid for just one of them. They’re also giving free upgrades to those who already own one of the components, so check your email if you do. (Mine was caught in a spam filter, which is apparently common, based on the G+ thread.)