1. What is it specifically you are looking to do in that city? Be a band? Open a studio? Be a label? Just enjoy music? Other?
2. Perhaps consider not what IS the best music scene but what WILL be the best music scene given your answer above PLUS the infrastructure of that city, possibilities, etc.
For example: Portland is an amazing up and coming indie music scene. I came from there (Dirty Halo), Dandy Warhols, Everclear, now Modest Mouse, guys from Death Cab, Shins, Gang of Four, and so on... but to be a studio in that town, ouch!
L.A., where I am now (but would love to live back in Portland) may be at it's lowest point for music, but you simply can't beat the infrastructure, resources and talent pool almost anywhere...but I hate "living" here. I mean, AMAZING players, studios, gear rental, labels, EVERYTHING is right here... but it is hard living.
So, perhaps consider those aspects and let us know what your objective is and we can better help.
DIRTY HALO www.dirtyhalo.com
P.S. Best of luck... exciting adventure no matter where ya go!