Ugh, I suck at making top 5 etc. lists, so I'll just name a few.
ReDead- While it's my most loathed enemy as well, it's also one of my favourites. The reason for this is mostly how it's appearance changes in almost every game it has been in, and it's great fun seeing how Nintendo will come up with it's desing.
Stallord- The theme appears to be living dead, but fear not! There will other kinds of enemies as well. Stallord because he just kicks ***. I mean, when the battle begun, I waited for the entire thing to come out from the sand, and the battle would have taken place atop Arbiter's Grounds. So, yes, I was slightly disappointed since we never saw the entire thing rise from the sand.
Darknut- This enemy is just great fun battling against, and I always enjoy taking them on. Since they have heavy armor, and wide attack arsenal, and can block your attacks, it requires a more strategical way to defeat them, and forces your brain to do something else, than to just: "Press B, press B, press B, press B, done."'
Wizzrobe- These foes are cool, since they have different Magic based attacks, and can teleport across the room, and they require a more strategical way of defeating, like Darknuts, and are actually quite rare to come across, usually appearing only in dungeons etc.
Just to name a few of my personal favourites. And I didn't include any bosses (save for Stallord) or antagonists.