In the most recent 0.7.2 update, I started a process of usability enhancements in the run up to 1.0 to try and make the Alfred experience more predictable and consistent for new users. It's only during this process that you realise how very few options there are for fast 'single tap' hotkeys to perform certain tasks.
Tab Auto Complete
One of the very hardest changes I made was to the Tab behaviour - something which absolutely had to be done as Tab is synonymous with auto completion. Before I start, I will explain how Tab auto complete works in the Alfred file system navigation view and how efficient it makes finding a file you want.
If I have a photo called 'kittens15.jpg' in a folder called 'Aww Kitties' on my Desktop, I would use the following process to navigate to the file after bringing up Alfred:
~ takes me to my home folder de [enter] results filtered to 'Desktop', enter the folder aw [enter] results filtered to 'Aww Kitties', enter the folder k [tab] auto complete to 'kittens' 15 [tab] auto complete to 'kittens15.jpg'
Clearly having Tab as Auto Complete freakin' rocks... so what now?
Brain Dump Alert!
Warning: The following is a bit of a brain dump of some of the thoughts I had for changing the Tab behaviour.
1. Tab needs to be Auto Complete, nothing else
As you can action files in both the default Alfred default view and the file system view, the tab behaviour has to be consistent between these views. This rules out having Tab to perform an action completely.
2. The action key needs to be easy to find without looking
By making the action key ctrl or fn it will always be the bottom left key on the keyboard. This is very easy to find with your left pinky without taking your eyes away from the screen.
3. If you like scrolling, group all the action key with the arrows
By allowing the right arrow key to action, this means that you can find the file you want to action, then for example press right, down (to select open with), right, down (to select the application), then Enter to finalise the action. As an added bonus, on Apple laptops, this also makes the action key the bottom right key of the keyboard.
So there we have it
The Tab behaviour now rocks, and the action key is easy to find without having to look for it. But wait, there is one more thing... If you liked using Tab just because of the location on the keyboard, you have another option!
Remapping Caps Lock
If you don't use Caps Lock (I'm guessing you probably don't), in the OS X Keyboard preferences, you can select 'modifier keys' and remap Caps Lock to Ctrl which then works as the action key! Some have mentioned that this is the most comfortable key to find on the keyboard so everyone's a winner! :D