I do a lot of typing and programming so taking my hands off the keyboard to launch or switch to an application can become a bit of a pain. There is
ALT-TAB but it only lets you cycle through already running programs, not something that is not open already.
Spotlight is nice for finding weird things (like all the times you have mentioned the word banana in text documents) but it is just a little too slow for doing quick tasks like opening your favourite folders or launching an application.
