Joel Spolsky points to Steve Yegge's view on Agile. I've personally never had the chance to work using Agile methodologies - it was inconceivable in the companies I used to work for, and now I'm mostly involved in long-term research projects, where development is minimal.
Anyway, I think that the subject of Steve's post is a little misleading. In addition to depicting why he thinks Agile is mostly bad (comparing it to good and bad cholesterol), it also provides a very interesting insight of how it is to work at Google. Like many of the commenters, I think in most companies it's not a realistic approach. Nevertheless, I'm pretty sure every company could learn a few things from them, and at least adopt some of it.
Anyway, I really enjoyed reading that post - I usually avoid reading long posts, but I'm happy I didn't skip this one :-)