Thankfully it seems they are coming out with a fix for this in Eclipse 3.7. Since most of us are impatient and don't like waiting for fixes, one kind developer out there backported the fix into Eclipse 3.6.:
You can replace your <ECLIPSE_HOME>/plugins/
org.eclipse.jdt.core_3.6.1.v_A68_R36x.jar plugin with one from
and restart Eclipse. Content Assists will be much better. Just try it.
Don't forget backup your original plugins.
I have verified that this is working, and unlike other fixes which require you to download the entire Android source for each version you are working in, you can have this up and running in under a minute.