I LOVE regions. If I really think about it though, it's more a side-effect of the regions than the regions themselves. I usually have a few main regions in my classes: private members, properties, constructors, methods, static methods etc. This has the wonderful direct effect of when I open one of my classes and I want to find property blah, I can pop open the properties region and it's there (I know I can use the drop-downs at the top of the code window but that's no fun!). It also has the, arguably, more useful side-effect of keeping all like-things together, so that when new people look at the code, it's much harder for them to put new properties at the bottom of the file instead of with the other properties. My logic here is, let's face it, most of us coders are "OCD" in the sense that we like order and symmetry and things like that, so putting a property outside of the properties region that's already defined makes you feel 'icky' and you want to move it. That's my 37 cents anyway...
Typical n-tiered architecture: DB <-> Junk(0) <-> ... <-> Junk(n-1) <-> Pretty