You can do this if you install the Astro File Manager app (or possibly another file manager). Between Astro and the Dropbox app, I'm able to do pretty much whatever I need to do, between moving files around and uploading/downloading files between my tab and computer with relative ease.
It sounds like you may have no need for a tablet, that's up to you...I'm not gonna try to talk you into it. For me, it's a great portable device with nearly fully functional web browser. If I need a computer, I have one, but I find the tablet quite convenient and I'm quite satisfied with my purchase so far.
I agree that Android as a whole could stand to allow a little more flexibility as far what they lock down to root access only, but none the less it's still a very functional device. I have an HTC thunderbolt which I have rooted, but I'm not even sure that for what I need it for, I'm that worried about gaining root access to my Galaxy tab.