In the closing moments of Stargate Continuum, a huge crowning moment of SG-1. As SG-1 tries to return history to the way it was... the evil Que'tesh and hordes of Jaffa attack them. In an act of courage that almost dwarfs anything they did on the show, SG-1 gets blasted one by one as they take down the Jaffa. All of them die but not before Colonel Mitchell makes it back in time. He then has to wait 10 years to shoot that smug bastard Ba'al in the face and prevent him from altering history at all.
Daniel Jackson deserves special mention here, as he was fighting the Jaffa with only one (real) leg, having lost the other in the arctic. Daniel may be one hell of a nice guy, but he's more than capable of being a badass when the situation calls for it.
The entire movie qualifies as one giant one for Ba'al. He escapes execution and rewrites time to take over the galaxy "with style" , to the point Earth was happy with the new timeline, the replicators never got released, the Ori and Wraith didn't exist, and he'd win over Earth with charm... Too bad that he didn't think about one, tiny thing.
When SG-1 is called to the presidential bunker to advise President Hayes on the Goa'uld fleet, the President says they can either say 'I told you so' or stay and help. First thing Daniel does? Turn to leave, then turns back and shouts "I TOLD YOU SO!". That's right. Daniel calls out the President of the United States for his Too Dumb to Live attitude about their warnings.