I used to do a lot of object-oriented programming and found myself reading up a lot on how to do it well. When C++ was the dominant OOP language there was a very different set of best practices than have emerged since. Some of the newer ideas I know of are BDD, internal DSLs, and the importing of ideas from functional programming.

My question is: is there any consensus on the best way to develop object-oriented software today in the more modern languages such as C#, Ruby, and Python? And what are those practices? For instance, I rather like the idea of stateless objects but how many are actually using that in practice?

Or, is the state of the art to deemphasize the importance of OOP? This might be the case for some Python programmers but would be difficult for Rubyists.