In reverse order of who I want:
City - just no.
Barca/Juve - very hard ties that will take a lot of effort and intensity, and focus away from league games.
Utd - would strongly fancy us to progess, but another big distraction from the league.
Spurs - think we would dispatch them fairly easily, but Spurs is just not a proper CL QF tie.
Porto - easiest on paper, but a little dull.
Ajax - the perfect tie, especially being based in Amsterdam. Another European royalty match, but very winnable.