Hyperspaces extends and customizes Apple's implementation of Spaces. It lets you assign custom desktop pictures to each space for easy recognition (or just tint the desktop picture of each space a different color) and label each space -- useful if you routinely dedicate different spaces to different tasks. It also improves navigation among spaces by letting you configure a virtual map of where spaces are in relation to each other, and it offers hot keys for common Spaces tasks, such as adding or removing spaces and showing or hiding desktop icons in a space. Hyperspaces works with Mac OS X Leopard or later and costs $13.
SaneDesk is another Spaces enhancer that allows on-the-fly creation and deletion of spaces. It supports an unlimited number of spaces, each of which can be customized with its own desktop picture, set of desktop icons, and Dock (complete with unique Dock items and on-screen positioning). SaneDesk works with Mac OS X Leopard or later and costs $16.
Switché is a Snow Leopard-only utility that builds on the Exposé feature. It uses Apple's Cover Flow feature to show large, smooth 3D previews of running apps, windows, or spaces, allowing you to switch among them in an intuitive manner (similar to the swiping feature of Mission Control). Switché costs $8.
Auto-save and Versions
Auto-save isn't a new concept, nor is it specific to iOS. Many applications offer an option to either automatically save files at a set interval or to auto-save a backup (without changing the original file) that can be accessed if the application crashes.
Lion taps into that auto-save functionality in a new feature called Versions, which lets you view all past iterations of a document or other file that you've made changes to. In a way, it's an extension of Apple's Time Machine, which allows you to locate and restore files from a backup. Time Machine comes in very handy when you want to get back a file you've deleted or find an earlier version of a file before you made modifications to it.
However, while Time Machine makes hourly backups of each document, it keeps them only for 24 hours; it permanently saves only one backup of each document per day. Versions, on the other hand, saves and keeps a version each time you open or save a file. If a document is open for an extended period of time, a new version is stored every hour that it's open.
There are a couple of ways to get similar features right now.
For applications that don't offer an auto-save feature, there's ForeverSave, a utility that can provide auto-save features systemwide to any Mac running Mac OS X Leopard or later. You can select which applications can auto-save and when they auto-save (the default being anytime you switch applications).
Beyond simply auto-saving your work, ForeverSave can maintain multiple versions of your documents as you make changes to them, much as Lion's Versions does. You can even choose how many versions of auto-saved documents are maintained and when they are erased. ForeverSave also allows you to set multiple auto-save operations to serve as an extra backup.
Although an iOS-like auto-resume function -- the ability to close an app and later pick up exactly where you left off when you closed it -- isn't built into ForeverSave, its one-click restore option comes close.