Tough one. Right now I want that $200 Asus/Google pad when it materializes. Then i have $400 to go. My N9 works remarkably well as my everyday phone, but the camera is poor, and no shutter button sucks more and more. Thought I would get used to it, but no. So the only solution:

Google/Asus tablet $200
Nokia 808 PV $400
Sum $600