all of our vital documents are kept in a safety deposit box at the bank-birth/wedding certificates, passports, ss cards, titles to vehicles, copies of insurance policies (if you are ever emergency evacuated from your home as we once were-you want access to copies of your policies)....
I have file cabinet that has folders that are broken down by type-household appliances, electronics, vehicles, etc. in each folder there's an envelope with the pertinent info on individual items (warranty info, serial and model number)-the receipts for these end up in the safety deposit box b/c we have replacement value coverage on our homeowners so I want to be able, if the need arises to substantiate the quality/manufacturer when seeking replacement. I keep current (last few years of tax returns) in the cabinet-prior years I put in banker boxes in another area. I've kept all the documents for the 3 homes we've owned 'just in case' AND in the event we ever end up on one of those 'unclaimed property/money' state lists (we couldn't claim some $ for my late mom b/c the asset wasn't cross referenced with her social security number and we had no documentation that she ever lived at the last known address the company that turned the funds over to the state had on file). as far as bills go-if they are something that documents a purchase I may need to reference for insurance or taxes I keep them in those files. also-since American Express extends warranties on some items I retain those bills until that extended period expires. all instructional books and materials for kitchen appliances are in a folder that's filed with my cookbooks, anything else (like vehicles, yard equipment, electronics....) are in marked (by type) large zip lock bags in a plastic bin in the garage so they are easily accessible (I go through this about once a year and toss anything we no longer own-if we get rid of something to goodwill or such I include the documentation with the donation).
I'm with tvguy on making sure to keep vital docs on parents-you never know if you may need them (and I have file boxes w/all the info from administering their estates). we've got bc's, death certificates, ss cards, wedding certificates, military docs....all safely stored away just in case it's ever needed.
since we have a disabled child we also keep a wealth of school and medical records b/c as these kids age up to where they need services it's not uncommon for public and private agencies to require documentation that goes back decades to substantiate when a disability was first detected let alone diagnosed. I have a large ziplock bag on my bulletin board above my computer that I put any and every receipt that relates to dd's college expenses so that when tax time rolls around I've at least got that element at the ready.
lastly-dh and I love to read, and also watch movies. we have a large number of books we've collected as well as close to 1000 dvds, blue rays and vhs movies. my insurance agent and I were talking one day and she mentioned that in the event of major theft or damage to a home the most difficult thing for clients to remember and put together is a listing of things like books and movies. as a result we created a data base that lists our movies (with format), books, music (with format)-and separate lists for each kid's video games, gaming systems (and in dd's case-anime). we update it as items come in (they rarely go out

).