White Orange San Francisco (also called ZTE Blade) phone.
The phone is unlocked and rooted so you can use the carrier and software of your choice immediately by adding your SIM (I used it on Giff Gaff).
The phone is currently using Android 2.2 Froyo (MoDaCo Swedish Spring RLS5) but you can use any firmware of the many brilliant versions available on the web (e.g. Cyanogen).
The phone has a high resolution (800 x 480, 266 PPI) LCD screen which is better than the likes of the HTC Wildfire and the Samsung Galaxy Ace.