I have been a long-time fan of LaunchBar , the whole concept is amazing and has truly changed my daily computer usage. Simply hit the activation key (ctrl-spacebar by default) and type a few letters from the app's name and Launchbar presents you with a list of possible apps to launch. Every extra letter further condenses the results. It is intelligent as well, learning to recognise which apps you mean. And it's fast - the whole procedure of launching an app takes as long as typing a 4 letter word. For instance launching Apple's DVD Player is merely a question of typing ctrl-spacebar, d, v, return! The on-screen list updates with every keystroke so you can see what app you are choosing, but often-used apps will automatically float to the top of the list.
However, there is a new upstart on the scene! QuickSilver is very similar to LaunchBar, but it looks prettier
There are a selection of interfaces for it, but I think it's safe to say the bezel interface is the slickest. The activation key brings up a bezel centered on your screen and as you press keys the icon in the bezel changes. The bezel looks very similar to the built-in OS X application switcher - itself a rare example of a feature that Apple swiped from Windows rather than the other way around (no matter what the developers of LiteSwitchX would have you believe).
All-in-all, QuickSilver has all the functionality of LaunchBar, but it looks more "OS X-like". The sole problem was that QuickSilver was for a long time noticeably less responsive than LaunchBar, however this appears to have been fixed in the latest B25 version of Quicksilver. This new version is very snappy and compares nicely to LaunchBar in terms of speed. It also doesn't suffer from the quite frankly far-too-slow indexing rigamarole LaunchBar goes through at startup.
Thanks for the tip Dave, I'd never heard of Another Launcher until you mentioned it, but after some Googling I discovered it is now on version 4 and has been renamed Butler. I've heard of Butler
and it's all been good too! I just havent yet had the chance to try it, will give it a whirl this week
check out Another Launcher. It's fairly OS X like and much cheaper than LaunchBar (it's free!)