unbindall should be
the first entry in your config.cfg (so don't remove it) ... and under this, it rebinds all keys ...
if I don't forget it, I'm going to add my config in here, when I'm back at home
just make it readonly, before you try to modify it with steam ...
[edit]
here are the first few entries of my config.cfg (only the binds)
but I have to tell you, that I'm using an almost completely different config, than the ESFs default
... but you asked for it
unbindall
bind "TAB" "+showscores"
bind "ENTER" "+attack"
bind "ESCAPE" "cancelselect"
bind "SPACE" "+jump"
bind "'" "+moveup"
bind "+" "sizeup"
bind "," "change_class"
bind "-" "sizedown"
bind "0" "slot10"
bind "1" "slot1"
bind "2" "slot2"
bind "3" "slot3"
bind "4" "slot4"
bind "5" "slot5"
bind "6" "slot6"
bind "7" "slot7"
bind "8" "slot8"
bind "9" "slot9"
bind ";" "+mlook"
bind "=" "bot_menu"
bind "[" "invprev"
bind "]" "invnext"
bind "`" "toggleconsole"
bind "a" "+moveleft"
bind "b" "turbo"
bind "c" "ascend"
bind "d" "+moveright"
bind "e" "+block"
bind "f" "turbo"
bind "g" "+use"
bind "j" "say DON'T DISTURB IN MY 1on1(s) !!!"
bind "l" "kill"
bind "m" "change_team"
bind "n" "togglefly"
bind "q" "lastinv"
bind "r" "teleport"
bind "s" "+back"
bind "t" "teleport;teleport"
bind "u" "messagemode2"
bind "v" "+powerup"
bind "w" "+forward"
bind "x" "descend"
bind "y" "messagemode"
bind "z" "toggleview"
bind "~" "toggleconsole"
bind "UPARROW" "+forward"
bind "DOWNARROW" "+back"
bind "LEFTARROW" "+left"
bind "RIGHTARROW" "+right"
bind "ALT" "+strafe"
bind "CTRL" "+movedown"
bind "SHIFT" "+speed"
bind "F3" "credits"
bind "F4" "toggleview"
bind "F5" "snapshot"
bind "F6" "save quick"
bind "F7" "load quick"
bind "F8" "mp3player"
bind "F9" "scouter"
bind "F10" "quit prompt"
bind "INS" "+klook"
bind "PGDN" "+lookdown"
bind "PGUP" "+lookup"
bind "END" "centerview"
bind "MWHEELDOWN" "invnext"
bind "MWHEELUP" "invprev"
bind "MOUSE1" "+attack"
bind "MOUSE2" "+attack2"
bind "PAUSE" "pause"