Yes, the Marantz SR8002 is new and you can read our exclusive online review
here, so I don't think it will be replaced for a while. Haven't heard the Denon AVR-3808, so can't make a direct comparison (we've only tested the AVR-2808).
As for speakers, I think you should be looking at the likes of the Dali Ikon 6 5.1 package (£2238).