iTunes 9.0.1 & QuickTime: I'm only interested in Webcasts, formerly known as Podcasts. The Genius function doesn't do it for me, I'd rather do this with Pandora.com. Rent movies? Nah. I'll do Unbox Video with Amazon.com, as well as the music MP3s.
Mozilla Firefox 3.5.3: I'm still trying to figure out a way to manage opt-in cookies. Just for the heck of it, I've enabled notification each time a cookie is to be placed. The NoScript add-on also provides an interesting perspective, alerting you for each and every script that will run on the Web page. Still evaluating Zotero for scholarly research and citation management.
Google Chrome 3.0.195.21: Fast and stable, but it does choke on Web sites that auto-update, but this is not a major problem. My most-used browser, now.
Microsoft Security Essentials: Yes, I enable automatic updates for the second Tuesday security upgrades, and since I'm not running an MRI scanner I'm not encumbered by the FDA. Running XP SP3.