A bit of history....
Back in 1987, 20 years ago now, I bought my first computer, an Atari ST machine. Based on the Motorola 68000 series of CPU's. Loads faster than the then available Intel CPU's, it had a GUI instead of "stoopid DOS", used a mouse with drop-down menu's and had this g-i-g-a-n-t-i-c amount of memory of 1 Megabyte.
One of the first programs I "got" for it was THE Flight Simulator. Created by Sublogic, later acquired by Microsoft.
OK, let's move back a bit. I was born in 1948, which makes me an old man. I have known the OLD Amsterdam Schiphol, with its 3 runway system. Where one could literally wave another one off, looking out onto the tarmac and SEE the other person waving from behind his window. There were no jumbo's then, well, the jumbo's were Super Connies, and KLM still had "The Flying Dutchman" painted onto their aircraft in the old silver & blue scheme.
In my younger years - talking about being 12-14 years of age - I wanted to become an airline pilot. I was also wearing glasses at the time which made it impossible. So I finally decided to become a radio officer at merchant ships, because the radio officer at aircraft had died out already. Because of this I had my background in navigation and especially radio navigation already when I started simming in 1987, plus some knowledge of the phenomenon "weather". So, in 1987 an old dream became "reality", although a virtual reality. Sublogic's Flightsimulator II could run in 3 modes: 640x400 black&white, 640x200 in 4 colors and 320x200 in 16 colors. The color versions were colorfull yes, but blurry too. So I ran it in black&white "hi-detail". The Cessna 182 had a retractable gear, 2 NAV radio's, ADF and some gizmo's more. I took the stuff pretty serious, logged every flight. Flightsimulator's default airfield was Chicago Meigs. Perfect to learn the stuff. Miss the runway and you'll splash. I forgot how many splashes I experienced, but it took me around 20 hrs of flying time before I could "decently" land the thing. Thank Gawd this one had no autoland feature. It did have some basic autopilot features like a wing leveler, heading hold, altitude hold and a NAV lock. I've flown hundreds of hours with the thing, practising about everything I could. Of course it had its flaws: no matter where you were, a VOR would always indicate as long as you were within 70nm (their maximum range). The Learjet it had showed 125 KIAS at 500 ft but I measured it once and it turned out to be around 210 kts true speed. That was because of course I wanted to fly a jet, then tried to land it at O'Hare and found the longest runway not long enough to make a safe landing. Oh well. It featured a bunch of additional scenery disks. One of them, the Hawaiian Islands had additional fun: just west of Niihau Island, at an altitude of around 3000 ft was an "aerial hoop" and if you flew thru' it, it trigged a series of weird situations, like flying across the Egyptian pyramids, over a huge piano, thru' gigantic tubes, along a Chicago scenery on your right side but tilted to 90 degrees, and it always ended that you got spit out by Mauna Loa volcano at 15000 ft. You could try to dive back into the crater or the crater of Mauna Kea and experience more weird stuff. I never flew the early Intel version, so perhaps this was restricted to Atari users only?
Then in 1991 I bought Proflight (which was an Atari specific program): a Tornado simulator, also in B&W, and I learned more. This thing had really decent flight dynamics, no wonder because the thing had been programmed by a BAC flight engineer. Getting out of a stall was more here than with Flightsimulator, which only needed more power. This one learnt me: unload the wings or you won't get out, not even at speeds of M 0.80 on the indicator. It had one sensational feature: at any time you could hang the a/c "onto a wire", allowing every movement except for it would stay exactly at the same place. This was where I mastered getting out of impossible situations. The air radio navigation thing had had no real secrets for me since the beginning, which was certainly an advantage. I've always been more of an IFR than a VFR pilot, to be honest. Flightsimulator featured clouds: one lower layer and one upper layer, both definable. You either were IN the clouds or not, which meant visibility zero or perfect. The same was true for Proflight, but it had at least separate clouds. So you would fly into one cloud, exit it at the same level until the next cloud showed up. The next simulator (still on Atari in 1991) was the Airbus-320 thing. Great for everything BUT scenery. I learned about fuel calculations at different flight levels, because the program would evaluate every landing on amount of fuel still on board (which had to be 30 mins flying time), every pound less or more would take points off. The touchdown point: everything off the centerline took points off, everything in front of or beyond the touchdown point took points off. Everything 1/4 of a degree or more off the actual runway heading would take points off. Touchdown vertical speed had to be 200 ft/min, everything more took points off. Don't bump off and get another time airborne, it would deduct 50%. And a bad landing would get your rating down and getting your rating down too much would mean demotion. A crash would demote you for sure. The basic version had Europe, the later version incorporated US East and West Coast. It came with hi alt Jeppesen maps and tons of approach plates for most of the bigger airports it featured, and it featured a lot of airports. It also featured realistic behaviour: fuel consumption got less the higher you flew, but reaching its ceiling was hard when the a/c was fully loaded with pax and fuel. VOR's would not indicate unless you had one next to you on the ground. Up in the air you could get VOR's indicating at 400 miles out, provided you were at FL370 or over. And most VOR's had ranges which had been taken from official publications. In the program it worked like: at 5000 ft you can receive it up to 50 nm, at FL70 you can receive it up to 70 nm. Good stuff. Something similar for NDB's: at larger distances you had to account for local variation in combination with the ADF read-out, so depending on where you were you had to add 12 degs to the instrument indication or substract 17 degs.
In 1998 I moved from Atari to the Intel machine. One of the first things I purchased was a cheapo Flight Simulator, I think it was version 5 or mebbe 6. Meanwhile it had become a Microsoft product and they had done lots about it, but not the old time flaws. VOR's still had 70 miles radii etc etc. Not worth a dime, if you ask me. But then in 1999 I found Propilot and Fly! Both cost 50 bucks at the time, but hey.... these looked like something different. Propilot used the 3-DFX technology, so I bought a Voodoo-3 just for that and "Oh man, look at those clouds....." The incorporated ATC, "Oh man, listen to those voices". Well the ATC was typically American fastfood. Piper so-and-so, cleared for take-off. 15 secs later: Please expedite. Flying the Citation at approach speed, they would vector you around the pattern so damned fast as if you were a hi-performance acrobatic plane. But it was fun flying. All of the US, and the other option was almost all of Europe. No way of doing a transatlantic flight. Their scenery rendition was stunning, I did the Grand Canyon in a Baron once and it impressed me.
Fly! on the other hand didn't. It was unstable and it wasn't until I patched it with available patches later that I found it the best sim I ever bought. The whole world in it, OK, the scenery was only nice in the special scenery areas but generally speaking, it became my standard sim. Finally at last I could fly from Amsterdam to New York. Erm, with the Hawker 800, that was with landings on Kevlavik and Gander to refuel :-) Later on I acquired tons of additional planes like 747's, 737's, the C-47, taildraggers and the lot. Plus I got so many additional scenery areas that my HD wasn't large enough to accomodate it all. One of the nice recent experiences (meanwhile more than a year ago) was: file a greatcircle plan from Amsterdam to Sydney, zero wind, fetch the 747-SP and see how far we get. I flew the whole plan, paused for dinners and sleeping time, and over Australia got concerned about the amount of fuel I would still need and flying time to reach Sydney. I got down with literally 5 mins of fuel in the tank..... but it was at Sydney :-) By now, we're talking the end of 2007, I believe I have several thousand hours of simming time and the fun hasn't gone out of it.