Well i hate to bring up another sim here but

I absolutely love the way WW2OL does icons for planes, except I wish they wouldn't have the plane name, just the circle.
At long range the circle is full and it's small and has no color. As you get closer to it the circle (icon) gets larger and starts getting color (and the plane name or friendly name). As you get closer, once the color is on, the circle starts disapearing like a clock kind of. The gap in the circle starts off small but as you get closer the gap starts to enlarge. By the time you are about 50 to 100 yds behind the con there is no more icon only the plane name (wich I wish was gone)
The best part of this icon system though is that the icons don't apear right away, it takes a couple of seconds. so if you check 6 you can lose a bandit that was on your 12:00, that is if you're looking for the icon

In ww2ol I'd say that a good 70-75% of my kills never new I was there, and I get bounced alot too!
I also like the way IL2 does the icons. You can set it so it only shows the distance.
This is my biggest complaint about icons. When you have 30+ planes in front of you all you see are a bunch of neon numbers. That really takes away from the gameplay to me. At least in the mission theater I will be able to turn off enemy icons though
