think about what your long term goals are and choose accordingly. do you think you want to be a designer and move in the direction of design excellence? or do you see architecture as more of a business with design as your product? the assumption is that everyone wants to be a designer, but there are also those who enjoy the other aspects of the profession too - documentation specialists, renderers, spec writers, etc. and want to specialize in a firm big enough to allow that.

i did my first internship pre-architecture school schlepping papers around and making small revisions to CAD drawings at a medium sized office of above average reputation, but it was enough to convince me that i was in the right field.

did the starchitect thing towards the end of school and i can tell you it was absolutely amazing working with someone of that ability. but the trade-off is that at the junior level, you are just listening and following more than anything else. highly recommend working at a high calibre design office. worked my ass off and they treated me well, paid me well.

did the corporate thing overseas after and learned totally different stuff. mostly, how NOT to run a firm with the senior partner and branch manager basically at each others' throats. if you intend to have your own firm, definitely do the corporate thing and learn how everything runs. systems, standards, IT, fee proposals, etc. you'll need to know.

probably better to do the boutique thing first if you're uncertain as you can always go corporate after, but it's tougher to do the opposite. once you have a track record of names, it become easier to get into top notch firms. if you string together a bunch of corporate offices on your resume, it'll be a tougher sell. know that some people find the life at a boutique or starchitect office extremely stressful because it takes a certain type to enjoy it. it won't take long for you to realize if its right for you.