This was announced, or maybe just rumoured, to be a new feature in the up coming Snow Leopard version of Apple's OSX. Oh man, the Linux fanboys came out in force to say how they had that feature for years and this was proof Linux was the all conquering masterpiece.
Personally my favourite file browser trick is exclusive to Macs at the moment. Quick Look:
http://uk.youtube.com/watch?v=MqjH0_E4pxQIf anything, I don't understand why Apple never implemented audio along side the video and document viewing first time around.
Anyways, that's enough of my Apple fanboyism showing through.
The best tip I can offer a Mint newbie is to make the most out of Gnome-Do (Windows key + Spacebar, then type something in). Make sure you have all the plugins installed by clicking on the little arrow in the top right and going into the preferences. Urm, at least I think you can do that with the gnome-do installed in Mint. I personally use Do that much that I added the gnome-do repo so I always have the latest version. Once you get used to it you will find yourself never using the Mint Menu again.
(Gnome-do is based on a Mac app btw)