The scene when Troy appears on Gabriella's balcony in 1.
The looks on Mr Bolton and Mrs Montez's faces when they see Troy and Gabriella singing on stage.
Ryan and the Wildcats playing baseball together in the second movie. Considering the Wildcats, and especially Chad's, general opinion on theater to see them having a good natured competition is really sweet.
Ryan and Chad actually switch clothes afterward. Even disregarding the blatant Ho Yay its nice to see those polar opposites genuinly enjoying each others company.
Ryan and the East High gang working together on a number for the talent show. Even Troy looks touched when he sees it.
In fact, Ryan being able to really show off what he can do without being pushed into the shadows by his sister and being appreciated for it by people he had nothing to do with beforehand is quite touching. It's the first time we see him not being pushed around by Sharpay.
Sharpay awarding the Star Dazzle award to Ryan also counts. She just looks so proud of her brother.
Gabriella coming back and doing a duet with Troy after having left in "Every Day."
Gabriella teaching Troy how to waltz "Can I Have This Dance" on the rooftop garden and then telling him yes she'll go to the prom with him in "every language".
Also in the rooftop garden: The scene in the first film where Troy and Gabriella open up and admit to each other how much pressure they're both under and how lonely they are because of it. Troy even admits that the garden is the place he uses to get away from all the expectations. The fact he shares it with Gabriella - and obviously feels he can be himself not 'the basketball guy' with her - is heartwarming all on it's own.
The Wildcats reactions when Gabriella returns at the end of 3: Even though she screwed up and left, they're all just happy she's back. Pretty heartwarming for a character who started with no real friends.
Troy's graduation speech in 3. Tear Jerker, too, because damn, Zefron did it well.
As soon as he's done his dad puts on a basecap from Troy's college. It's small but it's very sweet to see how enthusiastic he is about his son's desicion.
During Troy's speech we get a closeup of Gabriella and Sharpay sitting next to each other and they look very comfortable, happy even. After all the drama they've found it in themselves to become friends.
Sharpay and Ryan in general get a few moments in. No matter how much she treats him like a stage hand or how different their opinions are on things, they genuinly love each other. Best shown that whenever Ryan does something good and gets praised for it Sharpay is always the first there to congratulate him.
I Want It All is the twins envisioning their dreams coming true. And they want to be together when it happens. For all her It's All About Me Sharpay wants her brother at her side.
Also, the Evans family is a walking CMOH. They are so ridiculously affectionate that one has to wonder why Ryan isn't as much of a Spoiled Brat as his sister.
Here's one involving the cast: They all stayed friends since the films, and when Monique Coleman was on Dancing With The Stars, Ashley Tisdale, Corbin Bleu, and Lucas Grabeel all showed up, brandishing pom-poms in East High colors to cheer for her.