Hard to suggest without knowing much about you.. but I might:
- Look at Hilton Wangfujing as a cash+points possibility
- Arriving that early implies overnight, so I would arrive and taxi into Wangfujing, take a nap, then:
- Hire a driver to the Great Wall for the next morning
- Wander the Forbidden City and other local intown sights that interest me. Maybe look at
moondog's one day Beijing thread.
- Spend the night, store bags in the morning and head out to the Great Wall.
- Return, have a dinner somewhere near the hotel, head back and pick up my bags and then taxi back to the airport for my flight.
- Be exhausted for my next flight