Get a Better Scanner
While I am pretty vigilant about scanning truly important documents into my computer (eg my business license and personalized letters), I tend to throw the minorly significant stuff into on of the poorly organized file cabinets that hold up my desk. That's mainly because my scanner (part of my all-in-one OfficeJet) is designed more for scanning photos than documents, and the resulting scans aren't searchable.
But the portable Fujistu ScanSnap S300, reviewed by LifeHacker, quickly and smartly scans text pages and saves them as searchable PDFs. At $250, it's not cheap, but it's the perfect way to organize your papers come tax timeand with adjustable guides, it can handle all paper sizes. Plus, since it's roughly the size of a thermos and charges directly from the usb cable, you can take it with you on business trips and instantly scan in your receipts. Versions are now available for both Windows and Mac users.