i have a scansnap and i love it! i have set up a few basic profiles (one-sided multiple pages, two-sided multiple pages, etc) and it is very easy to change scanning profiles on the fly. i've had mine for about a month and i have scanned every shred of paper in my filing cabinet and fire safe. it's quick and easy - even on the "best" scanning setting. i have it scan directly to an encrypted dropbox folder so it instantly uploads a version for me to access anywhere. i try to give each file a meaningful name, but it's also easy to search the contents of the pdf files once they've been "ocr-ed". i plan to create subfolders like warranties, instruction manuals, etc, but i haven't done that yet.
as i went through my files, i did end up discarding tons of stuff without scanning. i didn't need copies of old utility bills and such. i set up a paper filing system with a folder for each month and i'm just tossing receipts and such into the correct month until i get my credit card and bank statements. i only scan receipts for major purchases, but i toss the originals in the month files for 30-90 days in case i need to return something. i also tossed all of my instruction manuals and downloaded digital versions from the products' websites. the only ones i kept intact are for some of my more complicated tools where it is easier to take the manual out to the garage to walk myself through the process.
also, i scanned some things and kept the originals too. like my family's medical records. some have been copied so many times that my "original" is tough to decipher, and the scanned copy is even worse. basically i'm working from a "if my house burns down" mentality where having a poor copy is still better than no copy. i also scanned savings bonds and passports and the contents of everyone's wallets, just to have all of the info in the same place. i had to use my flatbed scanner for some of that.
some minor complaints: i bought a scansnap s300m which is a mac model that doesn't automatically ocr documents. if i'd realized before i bought it, i probably would have held out for the new model that is both mac and pc compatible and automatically ocrs. i have adobe acrobat, so i can get around the ocr problem fairly easily. the only other negative i have found is that i can't rename documents as i scan. you can set up a default name (like using a timestamp or scan#), but i find if i don't rename them to something meaningful immediately, they start to stack up.
in conclusion - the scansnap makes it dead easy to digitize almost any document, so even if you don't go the extra mile to organize everything afterward, you'll still have a copy safe in your digital pile if you are vigilant about getting it backed up to a safe place. that said, it is still a bit of work to organize the digital files. if you need more info, check out http://www.documentsnap.com/ - there's a lot of good stuff there.