There is so many greatest hits compilations; which is the best?

There are numerous Santana compilations,but I think this one would probably be your best bet...

DISC ONE
Jingo
Evil Ways
Soul Sacrifice
Black Magic Woman/Gypsy Queen
Oye Como Va
Samba Pa Ti
Everybody's Everything
No One To Depend On
Touissaint L'Overture
Guajira
La Fuente Del Ritmo
In A Silent Way (live)
Love,Devotion and Surrender
Mirage
Carnaval
Let The Children Play
Jugando

DISC TWO
She's Not There
Dance Sister Dance (Baila Mi Hermana) (live)
Europa (Earth's Cry Heaven's Smile)
Stormy
Well All Right
Open Invitation
Aquamarine
You Know That I Love You
All I Ever Wanted
Winning
Hold On
Nowhere To Run
Say It Again
Veracruz
Blues For Salvador
The Healer (featuring John Lee Hooker)

It's not a perfect compilation and it doesn't feature anything from his 90s albums,but if you wanna get familiar with the music of Santana,this is a great place to start.You'll eventually wanna go back and get the actual albums.