[thacounty]

Android shouldn't become slow even if you have only 20MB left. That isn't the way it handles memory, very different from a PC. WM would become slow if you had anything installed to the phone, Android won't.

The best thing to do is uninstall all the apps that you installed when the phone slowed down. Then, install one by one and see if it is that app. I can tell you that I have never used any security program so that could very well be the culprit.

Edit: One more thing, I have a ton of apps, 230MB free on A2SD2 and have no problems with the phone slowing down. That's why I think its an app. If you get a task killer you could kill each app one by one and see if that app being killed helps the phone. You said you are good with comps so you know which apps to never kill.