MacOS – Spotlight menu shows results, but Finder window doesn’t

Try rebuild index

From the Apple () menu, choose System Preferences.
Click Spotlight.
Click the Privacy tab.
Drag a folder or an entire volume (your hard drive) to the list.
If prompted for confirmation, click OK.
Remove the item or volume you just added to the list by clicking
it and then clicking the minus ("-") button.
Close Spotlight preferences.
Spotlight will re-index the contents of the folder or volume.

You can also use the command line to rebuild Spotlight’s index.
Open the Terminal application and enter the following command:

sudo mdutil -E /

Authenticate with your administrator password,
and a message appears indicating that the index will be rebuilt.
Spotlight rebuilds the index of your hard disk.
You can track the rebuilding progress by clicking the Spotlight menu.

Launching applications with Quicksilver the “manual” way is so fast, I’ve never even bothered assigning a keystroke for one. If you did want a keystroke, you could limit the scope so it’s not active in certain applications, or so it’s only active in certain applications.

Also note that Quicksilver will very quickly learn that when you type “it”, you want iTerm by default and not iTunes, so you won’t need to remove it from the results entirely. And unlike Spotlight, you can find iTerm2 by typing something like “trm”.