3. ASTRO File Manager
ASTRO is nothing more than a Windows-style file explorer, but if you’re into tinkering and directly installing Android APK files yourself, it’s essential to stick something like this on your phone. It makes your phone feel like a computer, and makes you feel like you’re in charge of it.
UPDATE: ASTRO still exists as a free ad-supported app, but you’ll have to pay for the full version without ads. Our new favourite file explorer app is listed below.