Since Spotlight was introduced in 10.4, users could press Command+Return when selecting a Spotlight menu result to reveal the file in the Finder.
The exceptions to this behavior were things like contacts, iCal events, and Mail messages (as noted in this hint from 2006). For those types of items, the corresponding application would open and display the content. This behavior has changed in 10.7 and the files are now revealed in the Finder when invoking this shortcut.
[crarko adds: You may of course also get the Quick Look preview of the item first, or select it and open it as before.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20111001162412889