I recently bought FS2004 after years of playing military flightsims (which had started to lose their appeal) and I'm already having a lot of fun. I plan to add nothing to the sim for the time being and just fly it in its original form but I'm sure the time will come when I will want to add content so I was hoping for a steer in the right direction.
There are things I like about FS2004 and a few things I don't so I thought I'd try to add stuff that minimises the negative aspects (for me that is, I appreciate that a lot of this is about personal choice/taste). There are also a bewildering number of add-ons out there and I can see it's possible to spend a small fortune!
Things I like
1) the structured tutorial material e.g. flying lessons-very immersive.
2) the scenery at medium and high altitude
3) the clouds
4) effects like sunset and sunrise, rain
5) the external aircraft models.
6) performance (high fps even on my 2005-vintage PC)
I'm less positive about these features
1) the water (looks like crumpled blue polythene)
2) ugly textures at low altitude
3) the cockpits (2d pits are functional but flat and lifeless, 3d cockpits have poor graphics)
4) the feeling of flying in isolation (no dynamic world around you)
I've found a few add-ons that look good from my perspective. The aircraft by Captain Sim look amazing (I like the animations, the feeling of "depth" and the attention to detail), also the Just Flight package that adds traffic and FS Passengers also look very interesting. I'm less sure about the scenery: improved textures are probably of more interest to me than accurate elevations. I like airfield detail (especially if it has animated features like moving vehicles and taxiing aircraft) and as I've mentioned good quality water especially if it has movement and reflections is a priority if such an add-onexists. But I also have to be careful about my fps on this old computer (which I have no plans to replace at the moment-specs are 3.2 Ghz P4 Prescott 2m, 2Gb DDR2, Geforce 7900GS 256 MB). I'd be really grateful for any suggestions.