Well, I just finished Homesick after having half-completed it before and I'll agree with everyone else that it was very good. Though I wouldn't say it was _THE_ campaign. The problem I have with homesick, and similar campaigns is that there is a need for a suspension of disbelief.
The thing about Homesick is that the allied ships, and the allied fighters get their butts kicked mission after mission but are always 100% for the next sortie (with a few red alert exceptions). So as the player you have to forget about that, and just have fun. In the FS2 main campaign for example, there may be a Sobek in three missions one after another, but its a different sobek each time.
Homesick is good in the character development department (though they'd almost certainly have to be mercs for their un-professionalism) and the story in general is pretty good. Though I don't adhere to some of the premises in the story either, such as any-ship exploding in subspace = a subspace collapse. It's a good device to begin the story, but is contradictory to the FS2 campaign (just another suspension of disbelief).
Something like Derelict is good, but has its faults as well. Such as regenerating shivans, or the shivan-knossos summoning ritual or whatever the heck was going on.
In the same way, Warzone is pretty good. But I never fully bought the whole mind-control bit.
So basically, to me any campaign which is:
A) Finished
B) Fun
. . . belongs in the hall of fame. There's no need to leave out campaigns, if even one person has a good time playing a campaign then it was worth making. The more missions the merrier I say . . . and in the end everyone will have their favourites.
Personally, I still like the official Volition campaigns the best, Silent Threat not included.