HTC Deisre Z £379.99 @ Amazon.
(Edit: Same price at Play.com)
Cheapest I've seen it if your like me and dont want a contract.
Phones4u are £439.99 when I was in today.
-Android phone with HTC Sense and 800MHz processing power
-3.7 inch touchscreen display with a slide out full QWERTY keyboard
-5.0 megapixel colour camera with auto focus and flashlight and 720p HD video recording
-Free voice guided Sat Nav with Google Maps
-Bluetooth, Wi-Fi and GPS