Preterite or Imperfect?
 

I've got this sentence:

No recuerdo la última noche que dormí bien.

I would have put dormir in the imperfect tense, since in the context of the paragraph this person has had an ongoing problem, but as you can see it is in the preterite. Would it have been terribly incorrect to have put in in the imperfect?

Thanks!

Not terribly incorrect, but probably not the most common thing (I would add “en”).

No recuerdo la última noche que dormí bien.
I don’t remember the last night I slept well.

No recuerdo la última noche en que dormía bien.
I don’t remember the last night when I was sleeping well.

Imperfect would have been quite wrong for first person. From the point of view of a person each instance of sleeping has definite beginning and end (to fall asleep and to wake up). By its own nature "la última noche en que dormí bien" has very definite boundaries.

You can say

No recuerdo la última noche en que (él/ella) dormía bien.

as a matter of context. For you sleeping is not an action with beginning and end but some circumstances when you were aware of the way she or he was sleeping.

Is this possible?

No recuerdo la última noche en que hube dormido bien.

It is possible, but not very usual... maybe a bit archaic...?

I would probably say something like,
No recuerdo la última noche en que había dormido bien.
No recuerdo la última noche en que dormí bien.

(But as a matter of fact, I always sleep very well... so probably I'd never say any of these in a month of Sundays... but you'll never know...) :)

As JPablo said, it's a somewhat dated, but you have to use that tense when you need to state that something ended in the past so other action may occur. That's not happening in your example.

Anyway, there's a lot of regional uses -always in popular or vulgar levels- that might use it in a similar way, always by adapting features of indigenous languages. That would be non-standard Spanish.

Qué tál?

No recuerdo la noche en que (yo) durmiera bien.

Pareciera más bien que nunca has dormido bien en la vida (o no recordaras haberlo hecho nunca). En ese caso el imperfecto del subjuntivo apunta más a negar la acción de "dormir bien" que la de "recordar".

Si tal es el caso, sería también más claro ponerlo "no recuerdo noche en que durmiera bien" o "no recuerdo una noche en que durmiera bien".

I see now. Thanks everyone!

You're welcome!