The Ultimate Doom
Favorites: E1M1, E1M4, E1M7, E1M8, E2M2, E2M8, E3M1, E3M3
Least Favorites: E3M2, E2M9, E4M2, E3M8
Doom II: Hell On Earth
Favorites: Map02, Map03, Map04, Map06, Map14, Map28
Least Favorites: Map12, Map13, Map21, Map24, Map30
TNT: Evilution
Honestly, they're all just kinda meh in my opinion. They aren't terrible, but none of them stand out too much for me.
The Plutonia Experiment
Favorites: Map11
Least Favorites: I don't really have any. Plutonia doesn't have any levels I hate or severely dislike. They're all damn good in my opinion. Hard as shit but damn good.