- the CoverFlow Finder and QuickLook — because it saves so much time if you’re working with a lot of different documents or images.
- Spaces — because you can get back the control over your screen and because it works great in combination with exposé
- Time Machine — because it makes backups really easy (and even better if you own TimeCapsule)
- Mail with RSS support — because you stay in touch with the latest stuff in just one program
- new FrontRow — because it supports podcasts better.
- and last but not least: Software-Update — Because you would miss the continuing updating of your Mac’s software, wouldn’t you? ;)
Are these features worth upgrading? I think they are if you use your Mac in a more ambitious way than just surfing the web and writing two emails a day. But probably most of the normal users can life easily without Leopard’s new key features — I couldn’t.