I like these:
Ad astra per aspera
To the stars through difficulty
Crudelius est quam mori semper timere mortem
It is more cruel to fear death all the time than to die
De inimico non loquaris sed cogites
Don't wish ill for your enemy; plan it
Me oportet propter praeceptum te nocere
I'm going to have to hurt you on principle
Post proelia praemia
After battles come rewards
Ubi concordia, ibi victoria
Where there is unity, there is victory
(someone probably already has this one)
and of course:
Clamo, clamatis, omnes clamamus pro glace lactis
I scream, you scream, we all scream for ice-cream.