Homescreen is blank on 2.2 Droid
Try this from the CM forums:

If you use ADW or LauncherPro and if after using any memory intensive application you hed back to your Homescreen... you know the drill.....lag, lag, redraw, redraw, then finally you are able to function again.


MAKE A NANDROID BACKUP
In your terminal application on your phone (if you have to ask what this is, Google it, download it from the market) enter...



su (enter) 
echo ro.HOME_APP_ADJ=1 &gt;&gt; /data/local.prop (enter)
reboot (enter)



If you want to undo what this command does, simply remove that toggle from: /data/local.prop, or if you did not have this file (like I did not) prior to the mod...remove it entirely

This is also from Bryan Denny's Answer to this question.

You'll probably still have a problem with foreground apps closing when you keep your launcher in memory but I think that's just an issue with trying to use too many memory intensive apps with a phone with 256 MB of RAM.

You can also try to take the memory priority management into your own hands with AutoKiller Memory Optimizer.  It allows you to set your own custom minfree priorities for Android to follow.