They're at $149 right now.
You can use camelcamelcamel.com to set a target price and they will email you when it reaches that price. Pretty handy.
Yup, the reason for the price increase is that Amazon ran out of stock, and the other sellers had higher prices. They've since adjusted their prices and I just ordered a pair from one of the other sellers (fulfilled by Amazon) for $149. They should arrive at the office Monday!
I'm still tempted to go pick up a pair of DT770/80s right now from Guitar Center, just to compare. But I don't really want to fuss with making a return, especially since these are the most high-end headphones I've ever bought and I'm sure I'll be more than happy with either set.