So once you have your modules laid out and basic framework down, what are so of those extra bits and pieces of "flavour" you like to add to your mission. Not so much weapons or units, but more "systems".

Most of the time I play single player so ACE doesn't do too much for me at the moment.
I do use Spyder's addons mostly for the civilian interactions. I'm currently trying Psychobastard's A3 Wounding System to give me a medic that actually does something, and to add a bit more to the medical side of things, dragging and carrying units etc.

I would prefer things that work in both single and multiplayer as one of the guys from work is keen to try running some missions after the stories I've been telling him.

Mostly I'm using an asymmetrical OPFOR and actually enjoy walking through towns, speaking to civilians, hearts and minds type stuff, but also the EOD side of things is pretty great too.
Anything that will add more atmosphere is welcome :)

You could disable the HUD (at least some things) and the third Person view for Immersion too. In my opinion ACE is perfect for better and more immersive gameplay, single and multiplayer. I do like JSRS too, since the sounds are more.. epic? Especially the BRRRRRRRT sounds awesome and brings a smile on my face every single time.
Spyder Addons is great for the civilian interaction, same goes for the Environment things like sheep n goats.
Another quite interesting Thing is VCOM AI Driving Mod/Script. AI not getting stuck in objects while driving or not beeing able to drive around an object is pretty bad for the Feeling.

Yeah I've got the audio warnings for IED's on and that's cool. TPW mods is great, but I'd like to stick to things that are both SP and MP compatible so I can play with AI on my own, but then also play with a friend without having to modify anything.

I've just started using VCOM AI driving, and yeah that's amazing the AI can actually drive from A to B without crashing 6-10 times and running down 20 civies. :)

ACE is one of those things that I'd really like to use, but mostly for the medical side of things (I like the idea of having to call in med evacs even for AI squad mates) and also the extra stuff involved with explosives, but seen as I'm playing with AI a lot of the time they really suck when it comes to ACE. It would be amazing if your squad AI medics knew how to use the medical system, but that's asking a bit much I think.

One thing I am just off to hunt down is a script I used to use which added random radio chatter when you're inside vehicles. Just to add that little bit more of a feeling of just being a small part of a bigger battle.

Found it

Is there something I can include which will add "intel" to enemies? LIke for instance after a small firefight searching one of them you find documents or a map in their inventory which gives you the location of a bomb making facility or HQ or something? I find finding and disarming IED's very rewarding.

Currently I'm playing around with Spyders Insurgency mission template, adding things to that almost as a "testbed" for other missions.

Thanks for the ideas guys, the more we add here the more everybody can boost the polish on their missions.

@JD_Wang You could take a look at Hazey's Insurgency
He did a really nice Job with the Intel you mentioned. Intel items are spawned inside houses and dropped by killed enemies with a adjustable Chance. Those items give you the Location of weapon Caches, but not the exact Position. First Intel items give you a Position with approx 1000m distance. After collecting some, it goes down till you reach 50m distance somewhen. Then you can start searching houses (you can start earlier, depending on the Population of houses in that area) for that box. If you find it, you can put a bomb down and blow it up. Then a new one is spawned randomly on the map and new Intel leads to that.
It's really nicely done and you can put it in every map and Mission already existing, since it's a nicely planned Framework.

Can't live without ACE3 now, the medical you can use on your own on AI if you want which is perfectly satisfactory for SP, the carrying system, deafness, Interface, ballistics, in fact its hugely transferable to SP.

I wish TPW would translate to MP as the knock down script is great for stopping the silly AI hitting the dirt on hit and bouncing up in a heartbeat. Anyone know any MP equuivalent?

I'm playing the game with alive,CBA3, ACE3, CUP and its great SP and MP and works with either how I like it.