PocketCloud Explore

"Search, view and organize files on your computers from your Android device"

This is what the developers say. Well I really needed an app like this, so I gave it a try. It's quite easy to set it up, and very easy to navigate and grab the files from your PC.
After you install the app on your android device, you will get a link to the PC companion. Install this, log in with your Gmail account and you are ready to go (just don't forget to play a bit with the setting on your PC: start the PC companion, go to folder settings, and then ADD the folders or drives you want to make accessible). <--- otherwise you will only be able to access "desktop" and shared files. After that step you are DONE. Now you can access all your files from your computer on the go.

"Leave the laptop behind and don’t be concerned with copying or syncing files – just grab anything you need whenever and wherever!"

I have to say that it works really well. It's still an early version, has a few bugs, but it's working and it has decent speed. I even tried to pull a 700MB clip from my PC, and the transfer rate was quite good (my PC's upload speed is fair/good).

"With PocketCloud Explore you can:
• Securely access your content without syncing or paying for extra cloud storage
• Open remote files with any of your Android apps (e.g. QuickOffice, DocumentsToGo)
• Search for files across your computers
• Unlimited video, photo, audio and file transfers: upload pictures to your desktop
• Simple file management: create, rename and delete folders or documents"

Now there are some drawbacks, like you can only access 1 PC (2 if you buy the app now, and more if you get the Premium membership), and you can't set the link to the transfers. All files will be on external storage in a folder called "PocketCloud".
Not that bad, maybe they will fix it in the near future, as the SGS2 has a built in "external storage" and I would like to save the files to my memory card (external-external storage :D ).
Not to mention that it would be GREAT to have the ability to push files from your phone to your PC.

The price is ~1$ for now, and will go as high as 5$ in the near future (it's a special launch price). No more syncing and uploading to cloud services, just leave the PC on and grab what you need wherever you are. IMO this app is worth the 1 or even 5$.