Here is a great setup
Forum.ArchosFans.com - View topic - Newbie Tips - Allen's Setup - A70 and A101
for the task manager i use "auto memory manager"
Also load something like launcherpro, ADW, or Zeam. I am using zeam as it seem to respond a little faster then then LP for me.
Also minimize the amount of widgets you are running. I went with a very minimalist design on my screen and I am loving the device.