Wow, as a newcomer to ArmA, I must say that this thread has been an immense help!
Right now, I'm only using SLX and a sound mod, but I'm frustrated that there are some features in SLX that I could easily do away with (SLX effects, etc.). As said before, it would be neat if it were more "modular" so that I could use addons like MaddMAtt's ArmA Effects.
Anyways, I think I'll use a combo of these listed mods instead of SLX for now.
Also, will these mods (especially the gameplay ones dealing with AI, ballistics, etc.)) cause any issues if I were to play online? Basically, do I need to create a separate shortcut without these gameplay mods enabled to play on a standard, unmodded server?