Microprose F19 Stealth fighter on the Atari ST was the first flight sim I played when I was about 11. That was a real sim, I can remember how fat the manual was and you had to learn all about radar signitures and how to keep your profile low depending on what kind of radar was being used on you.
It was hard, but it was one of my favourite games.
Looking at it now, hmmm great frame rate huh? lol
Tornado was the second sim I had and first for PC (My dads IBM PS2 which I beleive was a 286 and had a 16 mb hard drive lol). It didn't run too smooth though and I had to play that with the keyboard and with bleeper sound lol.