Still, for those curious...
1: Android can Run Multiple Apps at the Same Time
"Backgrounder" will give you basic multitasking. And "ProSwitcher" builds on it to give you wonderful, Pre-like task switching. Caveat - there just isn't enough memory in anything less then the 3GS to comfortably multitask.
2: Android Keeps Information Visible on Your Home Screen
It'll cost a few dollars, but I've been very happy using "LockInfo" to provide a useful lock screen. It's a must-have application for me - it goes a long way to making my iPhone feel like an actual PDA rather then just a toy.
4: Android Gives You Better Notifications
Not nearly as nice as the Android's, but "LockInfo" does a pretty good job of managing my notifications once I told it to suppress pop-ups when my phone's locked. Paired with "Notifier" to continue pestering me if I miss an important update, I'm pretty content.
8: Android Lets You Change Your Settings Faster
"SBSettings" makes changing settings a snap - just slide my finger across the status bar at the top of the screen to access it. Though I'm not a fan of the default appearance - do yourself a favor and install the "Deep HUD" theme for a cleaner interface.
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And while I'm advocated bits and bobs to match up with the Android user experience:
"Simple Background" is a nice bit of eye candy, if you want your iPhone to have the same sort of parallax scrolling wallpaper that Android enjoys.
"Inspell" gives you red squiggly misspelling highlighting and intuitive spelling correction. It's a fantastic addition. Honest question - does the Android have something like this?