This question revolves around the most times a character from the TNG era (including DS9, Voyager and movies) died.
This question involves spoilers. Do not read on if you haven't watched all the episodes/movies and don't want to know.
"Death" here includes, temporary death, brain death, reversed death, presumed death, holographic death, imagined death, hallucinated death. The death doesn't need to be portrayed on-screen. Repeated death in the same episode or portraying the same event counts as one death.
Examples to clarify what counts:
* In "Cause and Effect", everyone on board died (then it was undone in a time loop)
* In "Skin of Evil", Yar dies. After the events of "Yesterday's Enterprise", we learn in "Redemption Part II" that she died in the past.
* In "Tapestry", Picard dies on the operating table, and then comes back, possibly due to intenvention from Q.
* In "Timescape", everyone on-board except Picard, Data, La Forge, and Troi die when the Enterprise exploded, but the time reverses itself.
* In "Thine Own Self", holographic La Forge is sent to his death by Troi.
* In Star Trek Nemesis, Data dies.
The point is not to argue over whether a particular event constitutes death or not. If it looks like death or is called death, it probably counts.
Inevitably I will be editing this more to clarify more as needed.