I'm quite young so my story is short.
LO:MAC demo - I didn't liked it, it went to trashbin after few hours. It was too hard for me, but.
IL-2 - Nah, I don't like props but I liked physics.
FS2004 - It was good but I didn't liked collision model or lack of it.
LO:MAC 1.01 take 2 - This time I had more expirience in flying (on keyboard ;)) and I liked to fly A-10A and F-15C. After one week of learning I have decided to buy Logitech Attack 3. It was huge step forward, flying was very fluid. Totally my favourite sim from the past. I remember flying with some people via virtual lan.
Short adventure in FSX. It was quite good. I liked to fly Bombardier Learjet XR45. I made my first Free Track kit, it was crap, too low fps camera.