Consider the following scenario which I'm due to find myself in shortly: You're to begin coding a new project that will be a "community website" in ASP.NET and you have a completely blank canvas to work from. You have free reign to consider and evaluate (not necessarily use) any libraries and ways of working to try and produce the most efficient, fast and maintainable application with a great customer experience. Of course, ensuring that the risk of external dependences is worth it. Which external libraries would you use or consider for developing with or from? I don't want to suggest a limitation on the scope of the libraries and their purpose, but if you'd use it on any project or if you feel that it would be relevant for a Community website/application - then I am interested.
Although this may seem a little bit "the wrong way around", I still think this is an appropriate question for the start of a project. Things such as ELMAH that reduce the amount of work required and provide an excellent starting point for a project. There may be other libraries / frameworks that if built in from the start - offer a significant advantage to the project in the long run.
(Disclaimer: I was unsure how to phrase this question, but I'd done some searches and not found anything that really seems to answer this theme of question. Apologies in advance if it doesn't make a great deal of sense).