! The show's staff and writers occasionally make jokes about <PERSON>'s frequent "deaths" on the show. In the season 7 episode "Heroes", one of the SG teams examine some ancient ruins and a scientist says "Dr. <PERSON> is gonna die when he sees this!" to which another member (Col. <PERSON>, played by <PERSON>) responds "What?! Again?". Comparisons have also been made between <PERSON> and <PERSON> from the cartoon series South Park. <PERSON>'s first death is by staff blast while he defends <PERSON>; he is resurrected by <PERSON> with a sarcophagus in the film. <PERSON> flat lines in Season 4's "The Light". 715
He dies of radiation poisoning in season 5's "Meridian" and Ascends to a higher plane until he reappears in Season 7's "Fallen (part 1)". He is killed by <PERSON> at the very end of "Reckoning" and is seen at a midway point between Ascension and mortality before finally retaking human form in "Threads". <PERSON> is presumed dead after SG-1 is brainwashed to believe this in Season 1's "Fire and Water". <PERSON> also is killed by <PERSON> several times in a virtual reality system in Season 8's "Avatar". Other deaths generally involve <PERSON>'s teammates: they die together in "The Nox" (where they get resurrected by the Nox) and in the alternate future of "2010"; their robot versions are killed in "Double Jeopardy", <PERSON> being the first to die; and a Goa'uld-possessed alternate timeline version of <PERSON> is shot by <PERSON> in "Moebius", while in another timeline in the same episode, all of SG-1 are killed except <PERSON>.
-Wikipedia article on <PERSON>.
As <PERSON> pointed out in his comment, death becomes a little more difficult to define once we're dealing with SF medical tech that can resurrect characters from a point when they'd be considered biologically dead. The general population of the SGC has certainly perceived him as dead a number of times, starting from "Fire and Water" in season 1, though he was not actually dead. I would imagine that they are also referring to his ascension, which may not have counted as death from his perspective, but was probably close enough to it for everyone else. 663