Nightwing Vs. Sandman in: "Beach Brawl!"

 

Sure, The Sandman has taken steps to become a reformed criminal - but nobody told Nightwing that!  This is a rematch between these two.  They first clashed back in STF #3447, and Dick Grayson also faced Flint Marko along with the rest of the Sinister Six in STF #3738...

Captain America Vs. Deathstroke The Terminator

I think this would be a pretty evenly matched battle.  Both are adept at their weapons of choice and well versed in multiple fighting techniques.  Cap is at the peak of human perfection with the Super Soldier Serum running through his veins, but Slade Wilson has the strength of ten men, enhanced reflexes and a healing factor.  That may give Deathstroke a slight fighting edge, but with Cap being the far better strategist and having that never give up attitude, I would still give him the eventual win.