The one utility that I need above all else is Objective Development's now venerable LaunchBar. That sentiment may sound an awful like Jason Snell's when he wrote about the release of the LaunchBar 5 beta, but it's only because it's a fantastic product. Whether you're a Quicksilver refugee or just looking for a great application launcher/clipboard history manager/data finder, LaunchBar has something for you.
All the features from the beta are still there, including its new clipboard history (which allowed me, happily, to dump another piece of software), Quick Look support, and integration with iCal for creating new events and tasks. It also has AppleScript support, new and improved actions (for such things as copying URLs as TinyURLs, resizing images, and even controlling iTunes), and quick access to Services (all the rage now in Snow Leopard).
You'll note if you go to LaunchBar's Web site that the available version is 5.0.1. Was the original 5.0 final release missed? No, Objective Development jumped straight from 5.0rc4 to 5.0.1, so if you're a hardcore fan of the product like me, you don't need to feel any shame about perhaps missing a release.
Unlike Quicksilver, this is a paid product and this major new version carries some upgrade costs. Single seat licenses are available for €24 (about $36). Family licenses for 5 computers are available for €39 ($58). Upgrades from previous versions are available starting at €9 ($13).