Open up a shell and type busybox and you will be presented by the number of compiled in programs ready for use.
as for the debian idea: i had both debian and ubuntu on my phone, even ubuntu with gnome running
it is just not that comfortable to use. you have to start it somehow via bootdeb, you need to shutdown before you can restart your phone and all this. imho this is too much trouble if you just want some simple tools at hand. for example i have an alias as='adb shell', so whenever i want a command executed on android i just put as in front of it.
i'd prefer to have them statically linked ( whatever that means, i guess something like standalone executable), as they are easy to include in roms this way. correct me if i am wrong, more than typing make to compile something and i am so out of there...
fwiw here is my list of aliases i use when fooling around with android, remount is a script i created in /system/bin, you can guess what it does:
alias as='adb shell' alias asll='adb shell ls -alh' alias aslog='adb logcat|tee logcat.txt' alias asro='adb shell remount ro' alias asrw='adb shell remount rw' alias assd='adb shell mount /sdcard' alias cdhero='cd /media/data/hero' alias vnchero='vncviewer hero:5901' alias sshero='ssh root@hero -p 2222'