IL2 FB — including AEP if you want to try you hand at online gaming.

Lockon — for the modern stuff

FS2004 — for less violent trips and the associated sea of brilliant addons

Battlefield 1942 — not a true flight sim, but great fun

Combat Flight sim 3 — if you get bored of IL2 (as if)

Secret Weapons over Normandy — for some light hearted hollywood inspired action

Pacific fighters should be out soon, Fair strike for some rotary combat although I haven’t looked at this for some time.