I agree about "Masks." It may be odd, but I definitely have a soft spot for it.
"Move Along Home" is another one that I constantly see trashed, but to me it's the good kind of campy, not the bad kind. And it's doubly ironic that the kind of people who flip out over this episode are exactly the kind of people that the Wadi are rolling their eyes at at the end, for taking everything with deadly seriousness.
The last one for me is "Descent." I was surprised to see how much hate this episode gets, when I joined this forum. It will always be a favorite of mine. (It also
explains why I hate Seven of Nine. Seven's robot personality is completely contradicted by Hugh's character arc--there's no doubt Hugh is a highly emotional being...sometimes immature, but certainly not inhibited emotionally in any way.)