Unforgettable, Vis a Vis and One. Neither Paris nor Chakotay are interesting and episodes centered on them are disastrous. Omega Directive was very bad but at least pretended to be about something other than Seven worship and salacious scenes, unlike One with earned the third slot.
But it was a very strong season. Those four are the only real contenders for dogs. Even weaker episodes like Prey, Retrospect, Concerning Flight had some good points despite some flawed writing. (Well, Day of Honor was pretty feeble.)