As I have written in my initial switching post, one of the softs that i am missing under OSX is the magical PowerPro (PP) program for Windows.

PowerPro is a very small program but it is a real Swiss Army Knife with a very rich set of functionalities (I am sure that during all years I have used it, I have not been able to discover all of them!). I have first find Butler to replace PowerPro for some of the facilities, but inserting text templates (like different greetings in mails or small LateX snippets) was rather painful. First open the shortcuts screen of Butler, then type the alias for the snippet, then type return, etc. Under PowerPro, I could just type ;prop and PP would replace it with

begin{proposition}   

end{proposition}  

I was used to have at my disposition a whole set of such snippets for different softs, and was missing them under OSX.

Enter KeyBoard Maestro (Keyboard Maestro (KM))!

It is definitely not as powerful as PowerPro, but it brings the exact function that I was missing.
I can now type ;prop and get the corresponding snippet. Or type CTRL + F and activate the French spelling dictionary in FireFox (combining the very nice Quick Locale Switcher plugin with Keyboard Maestro). KM can do many other tricks (launching programs, resizing their windows, opening some default document by simulating clicks on menu items, etc.). It is not free, but it is not unaffordable either.

You can check its features from this page and, if you are convinced by its possibilities, you can order it from this page.

Update (2012): I have also discovered now Launchbar that brings some other aspects of PP that was missing in my setup.