Apple have obviously been looking at how other app developers have been creating their apps and seem to have favoured this idea of a slide out menu that is seen in many apps now. This combined with the multi-tasking that is now available really makes the iPhone much more efficient to use. No need to close an app and then open another you can just switch between the two fairly easily.
On a more technical note, apple seem to have spent a lot of time developing more energy efficient ways for the new OSX Maverick ( Should definitely have been called Sea Lion ). This from what they have said will give up to 12 hours of battery life in the 13" Mac Airs. This is something that really needed looking at, technology was getting faster and more powerful but the energy side was always lagging so it's nice that they have taken a look at various ways of combating these issues and it seems to have worked.
One final point is the Car technology that they talked about, i think if this really takes off then it will be really useful and would eliminate the need to carry around bulky hands free kits. This will definitely only be features available in the top models of cars I'm sure but over time it will become pretty standard.
Lots of exciting new things and I acn't wait to get my hands on iOS 7 and have a play around.
Keep it easy :)