I'd like to be able to change my SMS tones.
I'd also like a dedicated "power save feature" so if its selected high drain functions (such as location, push, 3g and wifi services etc) are suspended.
One thing i miss (that i had on a Nokia back on '03) was customisable timed profiles for ringtones and message tones etc. it was useful because back then i could set the phone to just vibrate on a call/sms during college hours and when it hit 4pm the phone would automatically switch over to audible alerts.
I think it would be great if in IOS Safari or OSX Safari you could "send" a webpage you are reading to another device, for example, if you're at your desk reading and you need to leave but would like to keep reading, just press the "send to iPad/iPhone/iMac" button. The first thing you see on that device when you turn it on is the exact part of the page you were at.
A lot of things here, couldn't think of just one!