I didn't get into any arguments, but I did come close after my presentation. It was something to do with why we're using C++ and our tag system vs. C# or something like that. The argument against the Bungie Way (TM) had to do with automatic language support for object persistence vs. rolling your own. I remarked that if I had to do it on my own, I'd probably use C#. But that isn't strictly true.
The main impetus for rolling your own over using an external package is flexibility; if there is software that can not only meet your current needs but your future needs as well (assuming you have the budget), it makes more sense to buy it than roll your own. If, however, nothing exists on the market that meets your future (most likely unknown) needs, then it behooves you to roll your own.
As far as I know, there is no commercial or MS friendly open source package out there that would provide the same level of functionality or flexibility that our tag system give us. And because what ultimately drives our games is content, i.e. stuff that we have to store on disk, a solution that does not scale to our needs is insufficient and cannot be used. In other words, it makes sense for us to roll our own.
Another notable aspect of GDC I discovered since I hung out with Marty and Jay a lot more was how much more fun the Audio track is vs. the rest of the conference. Maybe it's because Marty and Jay's marketing of me as an audio programming god has finally gotten to my head, or because the field of gaming audio is so much smaller in terms of people vs. the rest of the industry, but there is a very big sense of camraderie across all levels of gaming audio, from the one-man sound and music shops to the celebrities like Nobuo Uematsu and Marty. There is a distinct lack of one-upsmanship or arrogance that pervades the programming and design side of GDC. Then again, maybe people just don't do that as much around the Bungie sound guys.