YES! I love M!MorganxLucina!
I didn't marry Chrom in any of my playthroughs,and since they're never siblings, I think "why would I NOT ship these two?"
Some of my other favorites:
NoirexYarne (or NoirexBrady)
OwainxSevera
CynthiaxInigo
NahxGerome
LaurentxKjelle
I would pair Owain with Cynthia, but since they're always cousins for me, I kinda... shouldn't. I actually almost did until I finally realized they were cousins. That would have been awkward.