I am new to the WM as well. At first I tried a whole bunch of them, and quickly got rid of most of them. I find that simple is best. I use my Treo mostly for phone, contact and calendar.
I am using Pocket Informant, but the jury is still out on that one.
http://www.pocketinformant.com/produ...p_id=pi&dir=wm
A Today screen enhancer is a good idea, there are many examples on this forum.
I am also using UI Tweaker for changing the color schemes, very simple and useful and free.
http://handheld.softpedia.com/get/Tw...er-16493.shtml
I also am trying Wisbar Lite for its cascading menus, and Close buttoms.
http://www.lakeridgesoftware.com/pro...od=WisBar+Lite
MemMaid seems like an essential little tool for memory clean-up
http://www.dinarsoft.com/index.html