Anson, a PM on the IDE team of C#, discusses the different ways that Intellisense is used and the design decisions that need to be made to keep it useful for developers.
One of the features that we continually get positive comments on is IntelliSense. More specifically, virtually every user that we talk to likes completion lists. Interestingly, when asked about it most users say that they like IntelliSense because it helps them type. However, when we do user visits (a visit where we go and watch someone use Visual Studio instead of just asking them about it) we often see that a lot of folks use IntelliSense to browse as well as to type. Of course it’s completely reasonable to say that figuring out what to type is as important as the act of typing; actually, I’d argue it’s significantly more important.
Check out the full post here: Browsing vs. Typing