Keeper - password manager.
MemStatus - memory manager.
Netstat - shows the communication status of your phone (ports etc.).
RulePlus - simple, but useful ruler.
Worlsd Facts - World Factbook.
WordWeb - English Dictionary and Thesaurus.
MyDiary - diary.
Safe Notes - note taking.
Balance - bank accounts managing, expenditures etc. (Very simple, but effective).
IOU UOI - simple app to keep track of your borrowing and lending.
mGifts - to manage gifts for events etc.
World Map - a simple, but useful world map.