I probably own and have played around 30 flight sims so I will just mention the WW2 ones.
My first flight sim of any era, as with so many of you, was Their finest hour, BOB. That kept me occupied on our Tandy 16 color (8mhz i think) for years until I saw Aces of the Pacific. I coveted that game but didnt have the computer power for it. Later my dad bought a new 486 (50mhz) and my first purchase was Aces of the Pacific. The computer came bundled with SWOTL as well, so for most of my high school years, whenever I played WW2 flight sims, I played those two. I still have never seen a sim that was as much fun from the strategic aspect as SWOTL, although I just recently bought Mig Alley and it seems to have an awesome strategic game, although not quite the level of micromanagement of everything that SWOTL did. My next WW2 sim was European Air War, which is probably the 2d best WW2 flight sim I own today, after AH. EAW was just plain awesome in every way, it makes my top 10 list of favorite flight sims from any era. A friend of mine gave me Janes WW2 fighters, but I never could really get into the game although it looks really pretty. I also had Luftwaffe Commander, which was a pretty cool sim, being the only sim I ever heard of that modelled the Spanish Civil War. When I was in college I played with SDOE a little bit, but never really got into it either, although I admired its physics modeling. I also tried to play Air Warrior 3, but it never would work right on the lab computers. I played Warbirds a little bit on a friends account or something, but I was always broke, so I never could afford an online flight sim at that time. After I graduated I found AH from a review on combatsim.com. It sounded like an awesome sim, so I tried the 2 weeks free. I was immediately and permanantly hooked. The 30.00 a week initially struck me as too much to pay, but of course I was unable to stay away. I was about to sign up again anyway, but when I heard that the price had been reduced I immediately came back. Ever since then, I have been unable to play other flight sims much at all, since all the time I have available for computer flying is used on this one. The only thing I didnt like was the unavailability of a historical theatre. With the addition of the CT, AH is as nearly perfect as any simulator I have ever seen. There are several WW2 sims out there I want to try out (rowans BoB, Il-2, CFS-3, B-17II) but I just dont have the time for more than one, and this is the one.