i'm actually mostly with bonvie here (except the postgame comments after burrows' OT goal, which is completely irrelevant in my opinion). while luongo no doubt was excellent in the three games the canucks won, he was mediocre-to-terrible in the four games they lost.
and, as happened in the three chicago series as well, when the team's wheels start falling off (usually the defense), so do luongo's. despite his very very good regular season record, that keeps him from being any higher than giacomin/vachon/beezer status despite the fact that he has had moments in the playoffs as good as almost any goalie of his generation ('07 against dallas, certain points in the '11 finals run).
i don't think it's quite as cut-and-dry as the team loses confidence in him, or that the team loses confidence in itself, when he falters. it's been, to this point, a mentally weak group and they all lose confidence collectively. but that's what you want your superstar goalie to do; you want him to be patrick roy and say, "i got this one, guys." if the team can only manage one goal on tim thomas, then luongo has to get a shutout. easier said than done, but we are talking about the greatest goalies of all time here.
all that said, i still think he's probably higher than giacomin given his longevity and otherwise nearly identical achievements. it's just that luongo's playoff failures are fresher in our minds than giacomin's were (i obviously didn't see them, but i understand that giacomin's were not pretty either).
depending on how the rest of luongo's career goes, and it's almost impossible to speculate what will happen at this point, i think he has a chance of catching cujo just by continuing to compile 30 win seasons. but he'd have to really put it together in the playoffs to get any higher than that. i foresee lively debates about luongo vs. thomas, actually. you'd want to go with luongo due to nearly as high of a peak and a much much much longer prime, but, as bonvie said, we all saw the '11 finals and after seeing that, luongo > thomas is pretty hard to accept.