I would have picked the Tennis Match scene (because I adore it), but it misses the point of the play, that Rosencrantz and Guildenstern are characters without a play in between their scenes in Hamlet.
That said, in all honesty, I prefer Shakespeare’s comedies to any of his other plays, and of those, I really only have six favorites, in no particular order: Twelfth Night, Taming of the Shrew, All’s Well That Ends Well, Much Ado About Nothing, A Midsummer Night’s Dream and The Tempest.
Picking these to highlight presents a different problem – how to choose WHICH version to include – and I’ve avoided the problem altogether by highlighting the genre instead.
Meanwhile, when you have the chance to watch the whole movie, put Rosencrantz and Guildenstern Are Dead on your Must Watch list. Trust me.