I have a Google Nexus S, 16GB, unlocked, and unrooted running Android 4.0.3 (latest update ICS). It is in good used condition (a couple of small marks on the body). Very nice 4 inch SuperAMOLED curved screen. Front facing camera and NFC chip onboard. Comes with box etc, plus a spare battery.
I am interested in giving Windows Phone or iOS a try and like the Nokia Lumia 800. I would also be interested in an iPhone 4. Must be unlocked or on O2.
I may offer some cash as well since the iPhone and Lumia have a bit better resale value.
Get in touch if you want a good Android Phone with the latest software updates.