42s - a very nice RPN calculator, and open source
flightcontrol - very cool game
ocarina - impromptu music maker
BOMRadar - useful to get an idea of cloud cover
TouchTerm/iSSH - handy for remoting
skyvoyager - sky chart
starmap - sky chart
FlatLux - last resort red torch
And finally, an app I wrote: geonote
*shameless plug*
http://itunes.apple.com/WebObjects/M...317860964&mt=8
It is free too
