There are two seperate debates going on in this thread (I just finished reading the whole fuckin thing) - whether the judgement was correct, and whether she was innocent.
From everything I've heard, the judgement was probably fairly lenient, as Corby's defense did very little to refute the prosecution's claims and establish reasonable doubt. If the defense had raised all the holes - the missing video evidence, the problems with the forensics etc. - then there would be genuine and strong cause to find her innocent, but basically all they relied on was circumstantial evidence - baggage handlers could've done it because they're being investigated now, it doesn't really make sense for her to do it etc. For that reason, I believe that she has a pretty good chance on appeal, if she gets a better defence team.
As to her guilt, well, no-one can really know for certain, as has been said. But it does seem suss that she'd go over to Bali several times, refuse to open her bag, take a bodyboard bag in the first place, and all that. And even worse is the fact that there's been no plausible explanation given to refute those claims.
And as for the argument that the pot would be worth more in Australia, apparently there's a big trade in westerners buying from westerners in Bali, because tourists are suspicious of locals selling when there's such large penalties.