My argument isn't about star wars as star wars, it's about star wars = something in real science which is exactly what you're arguing (and is what is inherently being argued when real units are thrown around).
So no concession for you

Originally posted by Woolie Wool
-In Warhammer 40,000...
-In the Culture novels...
-In FreeSpace...
-In Andromeda...
-In Star Trek...
-The missiles of the B5 Shadow planet killer are estimated at at least 50 gigatons each due to the total sterilization of the target world.
Except for Exterminatus, none of these situations draw many complaints, even though many are far more outlandish than Base Delta Zero and 200-gigaton turbolasers (*cough* gridfire *cough).
First, none of the other serious contenders here try to actually canonically put actual units to their weapons. Nevermind that they don't claim fusion as the power source. But I'll humor you:
Warhammer40k: yeah, that one's crap. Virus setting the atmosphere on fire and all that. Then again, no one's ever claimed WH40k has tried to set itself against anything resembling reality.
Gridfire: haven't read that series, so I have no idea what the context is. It's not near as mainstream as SW, but I can't really contest how preposterous that one is. If your numbers are accurate, then I agree that it's a preposterous amount of energy. No argument. Of course, you didn't mention a power source so I can only assume it's something equally fantastic.
Freespace: I'm glad you brought this one up, actually. Both of the things you're using as extreme rely on extra physics that are defined by canon, not real technology like fusion. The Sathani did something to Capella through subspace, where normal laws of physics don't apply. We don't know what, but that's not the point. As for the lucifer, there's actually a good thread going about that right now in General Freespace, which I won't bring out here. But let's just say that Vasuda is still there and the damage wasn't even all that extreme on the planetary scale. Cities leveled, habitable landmass (on a desert planet, so not that much) destroyed, but that can be done easily with 13 hours of 20-megaton-level shots at a rate of 1-2 per minute. And any weapon using more than the megaton range uses a non-conventional warhead which could have a much higher yield than a fusion explosion, which is actually less efficient than a contained reaction.
Andromeda: again, we're not depending on power-generation as much as we are the ability to alter the internal dynamics of a star. Sci-fi, so I'll take it.
ST Doomsday machine: I'm going to ignore the armor bit, since what science knows as Neutronium can only exist within the gravetic compress of a neutron star. But the internal power source can again be whatever it wants (it sure isn't ever stated) so let it have a planet-vaporizing death ray for all I care. I'm not going to argue against scifi that has no context simply because there's no yardstick to compare it to.
B5 planet killer: with an anti-matter warhead of a metric ton or so, a 50 gigaton yeild is actually quite possible for a missile. Those missiles were huge too if memory serves. And we're still talking about one-shot deals here, not a repeating issue.
However, Star Wars occupies a unique position in that its creators have sanctioned preposterous levels of power without also providing a boundless energy source of some kind. Star Trek has its dylithium crystals and warp fields to explain where its power comes from, while B5 tries to limit its weapons to what it can reasonably get out of a power source. Star Wars, instead of using just a tad of restraint, gives weapons far more power than they are obviously using and then puts them under the power of a device that is well-understood (if not exploitable - we still know how much power we could get out, just not how to get it to work without putting more in) where it cannot possibly sustain that level of energy consumption. I don't care if star wars isn't real life, if you're going to tell me their ships use fusion, then make sure the systems running off of that reactor don't consume exponentially more power than a fusion reactor is ever going to put out.
Oh, and in
every sci-fi involving FTL, it is done either via an alternate plane of existance (subspace/hyperspace) or by space-time manipulation (warp). Even star wars.