Gotta agree with most of the above, especially affected by Lal and Sita.
Allow me to add Tasha's funeral scene in Skin of Evil
. I first saw this at a rather young age. I had been spoiled, and the scene, while adequate, didn't do much for me. This is not an episode I revisit regularly, but I find myself more saddened by it with each viewing and today consider it quite moving. Denise Crosby did very well with what she was given here, and Data and Picard's reflections on her passing are perfectly handled.
Ron Jones' music for the scene is also particularly moving and effective.