Forgive me for linking to my personal site, but it's the easiest for me to find the references: here are some of my favorite plug-ins.
(I used to have more but I don't use them so much any longer)
Google search bar:
http://mobilespoon.blogspot.com/2008...lugin-for.html
PDA Status - shows some nice status icons:
http://mobilespoon.blogspot.com/2008...r-windows.html
WeatherBug (it's not even a plugin, it takes just an icon):
http://mobilespoon.blogspot.com/2008...ws-mobile.html
Bati Bettery plugin:
http://mobilespoon.blogspot.com/2008...ry-plugin.html
A great configurable today clock:
http://mobilespoon.blogspot.com/2008...day-clock.html
And this one used to be my favorite: DavState - you can see shortcuts you added and also running programs - it may not look so, but it's cool, believe me.
http://www.freewarepocketpc.net/ppc-...tate-v1-5.html
Enjoy!