We use .NET Web Services--both non-WCF and WCF, though the overwhelming majority is non-WCF, for legacy reasons--pretty heavily, and as I was testing something in Fiddler, I noticed that the response body size was pretty large. Then I noticed that the request headers didn't have any Accept-Encoding headers.
After doing some digging, it appears that the default value for the property HttpWebClientProtocol.EnableDecompression (from the class of which all wsdl.exe-originated WS stubs derive) changed between .NET BCL versions 2.0 and 3.0. I'm curious as to the reason (which may be WCF-related), and further as to whether there are any other [pretty] fundamental changes that are pretty quiet when you simply link against a different library.