The third iteration of iPhone software doesn't just add features (more here) like copy and paste. There's a lot new going on in terms of usability and interface that every non-power user will appreciate.
Search Everything With Spotlight
Instead of digging through 10 screens for your apps, search them out just like in OS X through Spotlight.
Upgrade Applications Within Applications
Now, apps can solicit your business through in-app prompts. A game developer could offer to sell you more levels and a magazine could add issues to your subscription. The implementation could be annoying, like shareware and absurd microtransactions, or useful, seeing as you can buy desired upgrades within the application, bypassing the App Store when it's unnecessary.
Use Custom Accessory Controls
New custom applications can be designed to work with specific accessories. Your iPhone can become the control panel for any participating manufacturer's device.
Navigate Google Maps In Any Participating App, Along With Turn By Turn Directions
Do you like Yelp but you hate leaving Yelp to go to the proper Google Maps? Now that developers can embed Google Maps directly into their applications, complete with pinch zoom functionality, hopefully these days of inconvenience will be over—especially when coupled with new turn by turn directions support.
Cutting, Copying and Pasting Now Possible
Sounds simple enough. Double tap text to bring up cut/copy/paste options and drag left or right to expand your selection. Double tap again to paste, or shake the phone to undo. Since CC&P is part of the core software, it should work in all apps that want to use it.
Email Multiple Pictures At Once
Thanks to CC&P, users can copy multiple pictures and then paste them in an email to send all together. We don't have a nifty photo of this just yet.
Write Emails/SMS in Landscape Mode
Before, you had to use a third party application to write emails in landscape mode. Now, the wide keyboard comes to all core iPhone applications.
Send Photos and Audio Over MMS
The iPhone gets photo and voice recording support for multimedia messaging. Plus, you can forward messages and stuff, too.
Stream Music In Stereo Over Bluetooth
This small distinction snuck in amongst the bigger announcements, but the new software will allow Bluetooth audio to stream in non-gimped, A2DP stereo audio. This should be great for peripherals/accessories.
No, Apple did not reskin the iPhone UI, but they did make a few handfuls of little tweaks, many of which we'll end up using on a daily basis.