Jaguars are fast, sleek and loaded with features or at least, Apple's new Jaguar ($129) is. It's the latest upgrade to the Mac OS--10.2, if you're keeping count. Previous versions of OS X were criticized for being slower than their predecessor, OS 9, but Jaguar zooms on by. Graphics and text look smoother than ever and are put to good use in some neat new programs. There's iChat (compatible with AOL Instant Messenger), in which conversations take place in little speech balloons. Sherlock 3 will find movies, flight times and Yellow Pages listings in a click or two without the hassle of actually getting on the Internet. And there's a great new spam filter in the e-mail program. If you're a Mac user who's been holding out on OS X, it could be time to play around with a furry feline.