I will take everyone through several sites I've been working on lately and describe what modules I chose and why and how I set them up. I'm hoping it will be helpful both to hear the logic of why certain modules were used (or not used) and see how they are knit together.
I will demo a fishing tournament site (a Views extravaganza), a church site that is still in development (lots of Organic Groups and calendars), and perhaps others if there is time.
My tools include views to manage comments, send ad hoc email to users, display custom blocks on site landing pages, aggregate event results into spreadsheet-like tables with totals, and more.
Some of the modules used are CCK, Views, Views Bulk Operations, Views Calc, Viewfield, Token, Token Actions, and Organic Groups.