My favorite, if Apple’s demo was any indication, will be iPhoto for iOS. (Like GarageBand, it’s a $5 download, or a free upgrade if you bought an earlier iOS version.)
In some ways, it goes beyond iPhoto for the Mac, in that its editing tools can do more than affect an entire photo in one swoop. It offers brushes that let you dab with your fingers to brighten, darken, saturate, desaturate or otherwise enhance individual parts of a photo. That’s something you can do in Photoshop, but it’s never been possible in iPhoto. Multitouch is used cleverly; for example, with two fingers you can rotate a photo, zoom in and out, adjust the shadowy “vignette” framing, and so on.
Another new feature (also unavailable on the “real” iPhoto) lets you double-tap a photo — to auto-select all photos with very similar composition. It’s a fast way to select all the shots of, say, a family grouping in the same pose, in readiness for figuring out which one is the keeper. Somehow the software analyzes what’s actually in the photos and figures out which ones you shot of the same subject.