I'm sure someone else has already listed this but, currently (due to injuries) for the Reading game (15-9-12) I'd go with:
Walker Dawson (Kaboul if fit) Vertonghen BAE
Gylfi Dempsey (playing just behind Ade) Bale
Lennon and Defoe being utilised for 30mins EACH in the second half. Parker, Townsend, Brad, Naughton and Gallas, (Daws if Kaboul starts) if required.
I think Dempsey will offer more to the team and he will allow Gylfi, Bale and Dembele to be more involved in the attack. Once Reading are knackered, then Defoe and Lennon can take exploit any space.
I think Reading will close us down and work very hard. Dempsey's engine and work ethic will help support the midfield, I think he'll help the midfield link with the attack better than Defoe might. Defoe definitely needs time and I'd look to start him at home to QPR. Gylfi is creative and can help to unlock a team better than Lennon can IMO, so I'd start with him.