Apple released iTunes 7 about a fortnight ago with, among other features, support for movies from the iTunes Store (née iTunes Music Store). Reaction to its interface updates have been mixed, but I rather like the tweaks to the interface.
Having said that, if you use iTunes alongside the podcast-subscription tool Juice, you should probably hold off on the upgrade since there have been reports of incompatibilities between iTunes 7 and Juice. Basically, Juice is still able to download podcasts, but it’s unable to automatically add them to your iTunes library (as it normally would).
Of course, these incompatibilities pertain to iTunes version 7.00 and Juice version 2.2 (the current versions as I write this). If you’ve come across this entry and it’s hypothetically December 2006, the now-current versions of those apps may very well have solved those issues.
iTunes 7-based niggles aside, Juice still works very well with iTunes 6.x (to which I plan on downgrading this evening). In case you’re not familiar with the app, Juice is an open source “cross-platform podcast receiver” for Windows, OS X and Linux. While iTunes has built-in podcast support these days, I still prefer Juice for the extra features that it offers, including (optional) auto-expiration (delete episodes of Podcast XYZ after ## days), and (optional) genre-forcing (such as forcing all podcasts to the “Podcast” genre). Oh, and it also has a customizable scheduler, so that you can have it check for new podcasts at an interval which you specify (rather than the arbitrary interval defined in iTunes).