This is something I've implemented in a Game Library application, the ability to type a letter or a number and have the search box go instantly into focus and search through your library as you type. So basically no matter what you are doing in this library as soon as you press an alpha or numeric key instant search goes into action. It's fast (instant) and snappy etc.
Here is my problem, users can select and deselect game icons (which represent games in the library), I want when a game is selected to be able to use WASD keys to navigate as if I were to use the arrow keys, this would mean disabling the instant search feature, but would it be OK to have keys other then W,A,S,D launch the search box knowing that 80% of the time in the library a game would be selected and that there is a 4/32 chance that a game would start with the letter W,A,S,D?
It's a bit tricky question and I've been debating with my partner whether to have instant search completely disabled when a game is selected OR have every key other then WASD still launch the instant search.