One of the niceties of Lightroom 3 (and maybe older versions, I don’t know): a Dock-icon progress bar to indicate the progress of long import/export operations and an optional sound alert (ding!) when they’re done.
After using the Lightroom 3 beta for a few weeks, I’m sold. It’s much faster, more stable (even in beta), more polished, and more robust than Aperture. Apple should consider its ass thoroughly kicked on this one.
That was probably in the older version too. I know the CS4 apps have that as well.
