OCR/ICR

The best document management suite seems to be from Nuance, being in the market from when floppies where still being used. If only you use it, the plain Paperport 14 version sets you back only 99 US dollars.
The best way is to scan the documents (or import existing), tag them yourself (like "invoice", "business", "personal"). If you leave your PC on though, usually there's a scheduled task to run through the PDF's again with OCR. In no time, the search command "FC1155" would return the PDF where FC1155 is really there (for instance an invoice number).
Of course, if the scan is of bad quality, it could be that that number is not recognised (maybe recognised as "PCi11S"). Therefore, the most trustworthy ones are the one scanned properply (straight, sharp, clear and easy to read printed text).
There's still no magic that can OCR handwriting properly though.
If the suite is working for you and you later need to add more people in the work flow, you have to upgrade to the networked versions.

As you can see, it's different than just OCR. If that's what you want though, then just use the first post above me.