There may be a slew of file managers out there to choose from, but when it comes down to it, ASTRO is still my personal favorite. Maybe it's because I've been using since the OG Droid days. Maybe it's because of the continuous development. Or maybe because it just works. Regardless of the reason, there's no denying that it's easily one of the best choices when it comes to a file manager on Android. And as of today, it's even better.
ASTRO was updated with a few new features, including SkyDrive integration - which is in addition to existing support for Dropbox and Drive - as well as an in-app image viewer that supports rotation and sharing, and an all new text editor. The changelog notes that Box integration is coming soon, so we can probably expect to see that in the next update.
ASTRO is, of course, free in the Store.