My current cell phone is a Nokia N70. While this phone comes with a lot of useful applications, it is lacking in what I consider to be some important ways. Here is a list of some applications (freeware) that I deem worthy of use.
FExplorer – a very powerful filesystem explorer. It includes features like sending files via Bluetooth and capturing screenshots.
EggClock – beautifully simple countdown timer. Giant font and several beep options.
PocketCounter – a more sophisticated stopwatch that can count up, down, in sync with time-of-day, and supports things like lap times.
Triz – Tetris!
FreeMines – a Minesweeper clone. Use google to find its .sis file; I couldn’t find a permanent link.