I love plenty of fights in DBZ. Majin Vegeta vs Goku is definitely one of them. Another one is Raditz vs Goku and Piccolo.
Frieza vs Goku on planet Namek, both before and after his epic super saiyan awakening.
All 3 Broly movies' (even Bio Broly) battles. Broly was always a beast... too bad the Z version is a raging psychopath. Even so, I understood him, but I understand the new Broly even better and like what they did to revamp his personality and backstory.
Goku vs Beerus in Battle of the Gods, even when Vegeta caught Beerus off-guard with his super saiyan outburst after Beerus slapped Bulma.
Yeah, I'm a dedicated Z fan. lol I'm sure by now you all know why though.
Android 17 vs Piccolo fused with Kami.
And as much as I hated how they twisted Android 17 with the fusion of Hell Fighter 17, the fight was very enjoyable, especially when he let 18 distract him long enough for Goku to deliver the fatal blow.
Oh, and the full fight against Golden Frieza in Resurrection "F".