Safari 5 does have some new features tacked on. Notably, Reader allows viewers to browse online articles without distractions by presenting it "instantly in one continuous, clutter-free view." Essentially another window with ads and such dimmed out. Additionally, Apple sure is pushing their support for Bing by adding it to the Smart Search Field alongside Google and Yahoo! Search.
Developers will get access to programming for Safari 5, particularly in regards to the Extension tool in Reader.
The new version is available as a free download from Apple's site now. Note that it is only compatible with Mac OS X Leopard 10.5.8 or Snow Leopard 10.6.2 and later. PC users with Windows 7, Vista and XP SP2 can also head over for a free download too.