Ok, so this isn't exactly a fair fight on many levels.  Any two of these "ships" against the other is a pretty easy hands down call, but I'm posting this because I saw a "SDF-1 vs Battlestar Galactica" (Original Galactica) thread somewhere and said that was a pretty easy call.  In short, that fight lasts as long as it takes the SDF to spin up the Reflex Cannon.   
 
So, what do you think?  Here are my thoughts... 
 
SDF-1 vs Yamato: SDF-1 Wins.  Why?  Same reason.  The Wave Motion Cannon would punch a hole right through the SDF but the Reflex Cannon would vaporize the Yamato.  And I love the Yamato, but I'm not seeing a win here.  Add in the fighter compliments of both ships (the SDF is about 4 times bigger and has a city inside) and this gets one-sided quick.   
 
SDF vs Death Star:  Death Star Wins.  Why?  On the whole, the Death Star should beat the SDF in firepower.  Now, first Death Star only shot planets in Ep. IV, but in Ep. VI it shot Star Cruisers and killed them with one shot.  Quickly.  If the SDF-1 pulled this off and won, it would be tactics.  The Emperor was unable to see defeat, as if he were blind to it.  Gloval was a tactician which may be all it took to win.  But shot for shot, Death Star.  (In a debate with my wife, the person who wrote most of the Robotech stuff you see on the sight, she said SDF.  I'll let her defend that.  I think by the time the SDF realized the Death Star had a main gun, it would be specks of dust).   
 
Yamato vs Death Star: Tougher Call.  Death Star Wins.  Why?  Main Gun.  The Wave Motion Cannon would punch a hole straight through it but would it hit the reactor?  Maybe, maybe not.  One thing the Death Star did show regardless of how fast it could fire.  Accuracy.  A better fight would be the Super Star Destroyer Executor vs Yamato.  SSD Executor might take a shot from the Wave Motion Cannon and survive.  Then again, blow the bridge off and we all know what happened.  Down in flames.  Might want to work on that, Empire.   
 
SDF-1 vs Galactica (Let's go with the new Galactica): Reflex Cannon vs Nukes.  I still go with the SDF.  I think it could take a Nuke and keep going.  I don't think the Galactica could take a shot from the Reflex Cannon.  The same would go for Yamato vs Galactica.  The Wave Motion Cannon is a beast.  That equals Galactica Space Dust.   
 
So, there are a few scenarios.  Let me know what you think.  I can see it a couple of ways...it all depends on X.  But there is plenty of media out there to make a call.  What do you think?