When I built our home garage I installed a 60 amp subpanel in the garage fed from the main panel. When I added our addition, I installed another 60 amp subpanel for it fed again from the main panel.
Just because you're running a couple 60 amp subpanels does not mean you need a larger main panel. To run a 60 amp sub you need a 60 amp breaker in the main. In the average. I the current 100 amp panel I have I could potentially install twelve 60 amp subpanels. As long as the total draw on any of those subs doesn't exceed 60 amps the breaker won't blow and subsequently as long as the total draw of all circuits doesn't exceed 100 amps the main will never blow. In general, a 200 amp service is pissing money away.
