Mac OS X: It's been a while, but if you still miss launching applications from the menubar a la OS 9 (and earlier), Himmelbar gives you quick menubar access to every application on your hard drive.
Even if the application is outside of the Applications folder, Himmelbar will find it. Your Utilities will have a separate category too, so you don't have to enter a submenu to get to them. Since I have Parallels installed, I even ended up with a separate category for my Windows applications which can be launched directly from Himmelbar.
While this is pretty much all Himmelbar does, it's capable of a fair amount of customisation. For example, you can display subfolders if you want to, plus you can add additional search locations for Applications if it's not finding everything you want to display. It's even possible to search for applications on the network so you can add applications present on another machine.
HimmelBar is a free application and is available right now.