I just read a blog post on Lifehacker about using a one box filing system to save time.
I've done this for several years. I have to say its worked pretty well. 99% of what I pile (actually a folder in a file cabinet) I never use, the rare time I need something I can quickly figure out where in the pile to look based on date.
When at CES this year I ran into Xamance. They automate this system by scanning your pile into filing boxes (think paper sized and about 1 to 2" thick). Internally they OCR the results so you can search for what you need. When you look for a document it tells you which box and which sheet within the box is the one you want. Pretty neat. They call it Chaotic Filing.