1. "I Will Always Love You" (from "The Bodyguard"): This emotionally charged ballad showcases Houston's powerful vocals, particularly her soaring high notes and nuanced phrasing.
2. "And I Am Telling You I'm Not Going" (from "Dreamgirls"): This show-stopping number demands high-energy, vocal agility, and a wide range of emotions, making it a technically challenging and iconic performance.
3. "The Greatest Love of All" (from "Whitney"): This soaring anthem requires significant vocal control and emotional expressiveness.
4. "I Have Nothing" (from "The Bodyguard"): This emotional powerhouse demonstrates Houston's ability to convey pain and longing through her voice, paired with elaborate vocal runs.
5. "One Moment in Time" (from "The 1988 Olympics Album"): This uplifting song showcases Houston's ability to deliver energetic and inspiring performances, often requiring precise intonation and vocal clarity.
It's worth noting that these are subjective assessments, and different individuals may find other Whitney Houston songs more challenging to sing based on their vocal abilities and techniques.