@OfTheDamned is exactly right. I'm astounded to see posts of this type still popping up two years after Froyo resolved the issue. People are still treating Android like some rotten old Microsoft Operating, talking about freeing up memory as if it were a good thing
What's even funnier is how they now say they Understand that keeping memory free is not needed any more, but they still do it. Like its a compulsion or something.
Three things:
1 ICS is pretty much holding the number of Apps to a dozen already. Check the list for a few days to see.
2 "killing" apps that are in the background isn't freeing anything. The OS already knows that the resources can be used.
3 The likelihood that you are smarter than the army of Google engineers who designed these things is very slim.
I think the silly system monitoring tools cause more stress than Finals week.
Take the healthy hands challenge and stop monitoring your phone's memory for two weeks. I bet you forget to go back to doing it and enjoy using the phone more.