Or let the players chose from all of the ideas above.

ok time for someone to shine in this topic
press Z then number from1-9 to choose a command
press X then number from1-9 to choose a command

@Custos, Lexsym:
(The following idea is taken from Soldat, since it works well there).
Use Alt+letter for a command/taunt.
Could have a 'taunt.txt' file with the list (each line in the file having 0: 1: .... a: b:) so you could define custom taunts. Maybe have the prefix ^ which denoted it was for team chat..

R is for reload

We have a lots of free keys on the keyboard, so everybody can give orders and responses with only one key.
F: Follow me!
E: Enemy spotted!
C: Cover me!
R: Roger!
N: Negative!
U: Under heavy fire!
I: Defend the Intel!
Or choose it from a menu like in Unreal Tournament "V" key.

also shift is to walk!!

Im just saiyan

Arrow keys????

I'm sorry, I don't play like this
http://www.youtube.com/watch?v=u8qgehH3kEQ

I was thinking what if you hold shift and use the arrow keys to select the command from the little wheel, after you select just let go of the keys to make your choice. Everyone else will hold shift and press y for yes or n for no (doesn't mean they will do it but it would still be much more fun to play as a team.) Support means that you "should" stay in a group, defend means well just defend something like maybe intel, maybe a fucking retarded building that is being used as a tactical position. Grief you select and shoot the person who is griefing and it will mark them for everyone else to see. Maybe add some more buttons for spotting, like replace grief with spot and it will mark enemys for your allies to see, it will tag griefing allies too.

It seems like a cool concept to work as a team, but it's just a thought.

http://img845.imageshack.us/img845/3566/hellyeav.jpg