Our full-scale MacBook Migrant coverage starts tomorrow, but it seems appropriate to kick off before that with the two keyboard shortcuts that anyone moving from Windows will find essential and useful.
The first is Command-Space, which opens up the Spotlight search dialog which lets you search through documents, apps and system settings on your Mac. If you've moved from Windows 7 or Vista and have been in the habit of using the Start menu search dialog, this is pretty much the direct equivalent. While you're learning where preferences and other options live in the Apple universe, it's often a faster way to learn the answer than trying to go online and search. (Mouse enthusiasts can simply click on the magnifying glass in the top-right corner.)
The second is Command-Tab, which alternates between open applications in roughly the same fashion as Alt-Tab on Windows. This is arguably the easiest way to see which apps are already open (active apps are indicated in the Dock at the bottom of the screen with a dot underneath them, but this isn't particularly evident if the Dock is crowded with all the default apps). Keyboard enthusiasts can also use the Q key to quit an app or the H key to hide it (we'll get to Mac app hiding later in the week).
MacBook Migrant is a week-long series of posts highlighting tricks new or aspiring Mac owners familiar with Windows can use to ease the transition.