Recently one of my colleagues (Dukes) and I were developing a module and he is one of those guys who has memorized every keyboard shortcut for Visual Studio and I noticed him "Attaching to a Process" (CTRL + ALT + P). Me being a traditional style developer I have always just reloaded the application using the trusty F5. We were involved in some client specific business logic and I just made a mental note at the time.
Recently, I've started using the Attach to Process (then select aspnet_wp.exe and Attach) as the way to test logic and I have to say that it is much faster than F5 even with cached authentication information and not logging in each time.
If you are like me and you are a habitual F5er, give attach to process a try, old habits are hard to break but this one will save you a significant amount of time over the course of a day, week or your career!