OK, now I feel better. Perhaps I jumped the gun with my previous post.
Rich Turner gave an awesome presentation – totally on the mark from start to end.
He was very, very clear that the prescriptive guidance is to use asmx (web services) to cross service boundaries and to use Enterprise Services (COM+), MSMQ, Remoting or asmx inside a service boundary.
Note that inside a service might be multiple tiers. Multiple physical tiers. You might cross network boundaries (though that should be minimized), but that’s OK. This is all inside your service, within your control. Since it is inside your control, you should choose the appropriate technology based on all criteria (such as performance, transactional support, security, infrastructure support, deployment and so forth).
This is the best and most clear guidance I’ve heard from Microsoft yet. Very nice!