http://www.youtube.com/watch?v=5zhS4DuML5Q
Stunning.

"The fact that every noise you hear, every bullet you see, every man you shoot at, every aircraft that flies past, is completely real, unscripted, and dynamic. Thats why everything is just so realistic, you dont need to script a large scale war.
This video just shows the pure beauty and scale of arma 2, the way the ai dynamically engages in battle, both on ground and in air. "
That's why i'm still impressed that this game exists, whatever bugs it might have. In terms of scale and ambition it is way ahead of the competition.
The problem with the singleplayer seems to be that they made it reliant on the AI pulling off very specific things, which in a random battlefield they can't do. They ought to have set the objectives to be much more general... cos if your job is to meet on guy, and the AI or a stray bullet kills him, then you are in trouble. If it is a larger scale objective then small issues like falling out of helicopters won't matter ;-)
http://www.youtube.com/watch?v=X03SVGktjLs&NR=1

We have very similar systems minus 2.4ghz and 4 gigs of ram. My system ran fine with everything on high. It's important to know that very high is suppose to much PC's to the limit and not many will be able to use the setting. You are probably the tip of the benchmark of what users can do. So assuming every one has at least a good mid range computer for maybe 3 or so years then everyone should be fine.

On my PC (C2D E6420 3.20 GHz, 4GB RAM, Radeon 4870) with all settings to high except AA i Have more than 45 fps.