In the interest of full disclosure: the Android phone I picked is the Samsung Galaxy SII. My two-year contract is up coming January, and three months in advance you're always allowed to extend your contract, and pick a new phone. So, I extended my contract for another two years (I've been with T-Mobile NL for like 7 years now and service is excellent for me, so no reason to switch), and bought the Galaxy SII for €149.95.
The courier delivered the phone only a few hours ago, so I'm still getting acclimated to Android. Coming from Windows Phone 7, it's clear Android is closer to the inconsistent mess of iOS than it is to the breathtakingly consistent and logical Metro interface, but a few nice things already stand out.
First, the fact that the menu button always gives you access to an application's settings - in iOS it's always a surprise how to find application-specific settings (a tab? A button? And where?), and in both iOS and WP7, it's always a guessing game where specific settings are located (in the Settings application, or in the application itself). Android is a breath of fresh air here.
Another nice thing are the widgets. It's nice to finally be able to put useful information on my homescreen instead of a bunch of nondescript icons (iOS) or remarkably limited live tiles (WP7).
Lastly, it's clear that while this phone is remarkably snappy and quick, the interface animations are not as smooth as those on iOS, and certainly not as smooth as those on Windows Phone 7 (seriously - Windows Phone 7 on single-core hardware is smoother than anything else I've seen; truly remarkable).
All in all, I'm happy so far, but of course, I've only had it for a few hours and I'm obviously still suffering from post-purchase rationalisation. In any case, let everyone know what your favourite Android applications, widgets, themes, and so on, are in the comments!