I remember Snow Leopard as a particularly stable release, but it's been so long this could easily be misremembering. One other thing that was notable about Snow Leopard, though, was that it was the last release before the iOSification of the Mac. Starting with Lion, Apple increasingly tried to unify the platforms and bring ideas and designs from iOS to the Mac, with mixed success.

For myself Snow Leopard holds a special place as the last "pure Mac" release and a culmination of a decade of Mac OS X releases. I skipped over Lion and Mountain Lion, finally getting back on the upgrade train with Mavricks, so I ran Snow Leopard for about four years.