I was pretty addicted to FS back a few years ago.
Joining a Virtual Airline adds some realism to FS. I was a "Pilot" for
Tradewind Virtual Airline. There are quite a few VAs around, but I like Tradewind because they weren't as strict on what lines you had to fly each month. They also have their own "Aircraft" that are painted in the Tradewind Livery. You can D/L any of their planes for free and take them for a spin. They have quite a few interesting planes.
FS 98 had all the real world Nav Aids in it, so I had purchased a set of High and Low Alt charts from
Jeppesen as well as some approach charts from most of the North American airports. These can be used in FS to chart your own paths between airports.
I've got FS 2002 Pro, but I could never get it to work correctly on my PC. It adds many features above FS98 and FS2000 such as Air Traffic Control and a very good Flight Mgmt System. FMS is cool because it will let you put in a set of waypoints and let the auto pilot fly to them. So basically all you have to do is take off and land.
Marty