Well, I imagine Vegeta would have dwelled on the sidelines and watched the
battle like Piccolo, Gohan, and Krillin, although he might not be as
exuberantly enthusiastic about it. At least not for Goku. I'm also sure when
the time of the Spirit Bomb came, he'd be reluctant to offer his energy, but
would have eventually done so. I'd also wonder when Frieza survived, had
Vegeta been his next target instead of Goku, Piccolo, or Krillin, and if he
survived, witnessing Goku transforming into a Super Saiyan and kicking his
ass basically, well, Vegeta would have been dumbfounded (in a good way).
Oh, and Vegeta might have been the one to get in that lucky kick on Frieza
in order to stall him so Goku could gather more energy for the Spirit Bomb,
or perhaps him and Piccolo could have made a coherent effort of working
together in order to stall Frieza more effectively, but I doubt it.
That's about it. *Just* my 2 cents.
--LegendarySSJ7