ok now back to answering your question.

overclock (use lehto's ulv (low voltage) 800Mhz kernel)
openssh server
simple brightness applet
checkout conversation ui; http://talk.maemo.org/showpost.php?p...&postcount=550
facebook chat using inbuilt Jabber; http://thenokiablog.com/2010/02/10/h...ut-of-the-box/
ATI85 Calculator (a must have)
Maepad (for Todo List)
OmWeather
Gnumeric (for excel spreadsheets, depends on your use)
ussd-widget + regexp to cut advertisement from your provider
games: angry birds, bounce, numpty physics, labyrinth lite
dslr camera sounds by buggzy (in share your mod thread)