Mac users, not a shy bunch to begin with, will be roaring over Tiger, the $129 operating-system upgrade Apple rolled out last week. The showstopper is Spotlight, a built-in hard-drive search. Just type in a word and Spotlight locates its appearance in documents, PDF files, photo and music labels, even e-mails. (Microsoft Entourage support is yet to come; in the meantime, export your messages to Apple's beefed-up Mail app.) Also new is Dashboard, a set of applications that perform little tasks or keep watch on stuff like stocks or flights. There's a dazzling way to run full-screen high-res video conferences. The upgraded Safari browser adds a privacy function (so you can surf without leaving a wake). Our installation went flawlessly, and we've already discovered cool new features--like photo-slide shows within e-mail. And we haven't even begun with the parental controls or the new program that automates your complicated desktop tasks.