Who says that Windows has all of the cool shortcuts? According to this bit below, there is one for Mac users that will help you to keep your iTunes RSS feeds in sync.

I found some extra iTunes keyboard shortcuts. The first is the most (only?) useful one, as I’ve needed its functionality before, but I don’t think it’s in a menu or anywhere else. To make iTunes resync the podcast items with their feed’s RSS (also has the side effect of disclosing all the triangles), do this:

Command-Option-] (right square bracket)

This is helpful for when you want iTunes to show you those podcasts that you’ve deleted, but are still on the RSS feed. If there’s a way to do it on a per-podcast basis, I couldn’t find it, but maybe someone will. Also, not nearly as useful, but also undocumented … to make the iTunes volume slider jump all the way down or up (this doesn’t affect mute/unmute), hit…

Command-Shift-Down Arrow (for zero volume) or Command-Shift-Up Arrow (for full volume)

Lastly, if you’re playing, the following key combo will stop iTunes. If you’re not playing and you press it, it will reset the position slider to 0:00:

Command-Option-Period key on numeric keypad (on a PowerBook, add in the Fn key, too). Source: Mac OS Hints