I'm going to have to disagree with you guys.
I really liked this episode.
Ok we've seen the Replicators before, we've seen Apophis before but what we've never seen is this situation before. Two of SG-1's main enemies of previous seasons and they are stuck in the middle.
Not only this but the Replicators have now figured out a way of getting to the Goa'uld system a whole lot quicker than the standard Goa'uld Mothership Hyperspeed. We know from previous episodes that the Replicators go where the technology is and they had already "consumed" the knowledge of Apophis' planet from the ships computers - who knows what technology they have there.
As far Apophis being dead - well it certainly seems so, but perhaps a Replicator "collective" faced with death could pull off something we could never imagine - integration with a living being. Maybe we'll see an Apophis hybrid. (think Lost in Space).
As for not knowing - where have you been ! Sky One has been running regular promo's during Sci-Fi Show adverts. Every UK Website has been giving reminders and all the Stargate Newsletters I know sent reminders too.
One thing which I do agree with was the irrelevent bantor between Jack & Jacob. It's something wi=hich I hoped would change in the new season and O'Neills character goes from bad to worse in this ep. He's a Colonel !! (to coin a phrase - as if !)
I would say that Tanith got included with the explosion that took out all of Apophis' fleet.
Considering that quite a few of the SG Team worked on it I think they'd be a little disappointed hearing their opener discussed this way. I say great opener - 8/10.