Couple things about Dropbox: many of you prefer SkyDrive--fair enough. Their mobile website is actually really nice. And there is no "official" app from them for Windows Phone.
So for those of us who do use Dropbox and regularly, there is really only one app out there that has constantly shown itself worthy, in our opinion: BoxFiles for Dropbox. The app recently received a hefty Mango update, which like all Mango apps, resulted in a much faster, smoother experience. In addition it had some graphics re-worked, new options and even a Live Tile which shows your used and remaining space left on your account. Slick.
Now in v2.5, the options continue with the addition of pinnable folders to your Start screen, for quick, easy 1-click access to all of your stuff. From there you can copy, delete, move, email, download, share, rename, etc. any of your files, making this feel quite robust. Finally, it's fairly Metro in design with minimalist graphics and text-focused, giving the app a more native feel. Oh and did we mention this has SkyDrive built into it? So for all of those who need a more feature-rich SkyDrive app, you may want to take this for a spin too.
The app goes for $1.29 with a free trial, which can be found here and gets our highest recommendation. There's also a free, ad-supported version with no SkyDrive support--that one can be found here.
Update: And we've just been just informed by the developer that v2.5 has a bug for new users looking to login/authenticate--basically you can't do it. If you're upgrading, like us, you're good to go and won't notice anything. The devs let us know that v2.6 will fix this and should be out in the next few days--so stand by for that one!