- a new version of Mail, with an elegant, widescreen layout inspired by the iPad; Conversations, which automatically groups related messages into one easy to read timeline; more powerful search; and support for Microsoft Exchange 2010;
- AirDrop, a remarkably simple way to copy files wirelessly from one Mac to another with no setup;
- Versions, which automatically saves successive versions of your document as you create it, and gives you an easy way to browse, edit and even revert to previous versions;
- Resume, which conveniently brings your apps back exactly how you left them when you restart your Mac or quit and relaunch an app;
- Auto Save, which automatically saves your documents as you work; the all new FileVault, that provides high performance full disk encryption for local and external drives, and the ability to wipe data from your Mac instantaneously; and
- Mac OS X Lion Server, which makes setting up a server easier than ever and adds support for managing Mac OS X Lion, iPhone, iPad and iPod touch devices.
All good stuff, but “Resume” is the most interesting — that stuff's straight out of iOS 4, and could be incredibly useful with an SSD.