I think the question is: are you ever going to need it? The second question would be: how accessible do you need it to be?
I have a series of folders for things I might need to lay a hand to quite quickly: Mortgage & house, Employment & tax, Bank & finance, Bills, Car, Important Documents (birth cert, marriage cert, degree certs), Receipts.
Mortgage - I'd keep most things. I don't get much paperwork for mine, and it's such a large amount of money, I figure I want to keep track of it. I also keep all my receipts for work on the house in there e.g. guarantees of workmanship.
Employment and tax- A copy of my contract, payslips for the last year, tax documents for the last 3-4 years (you might need to hold onto them for longer if you are self-employed).
Bank and finance - the last year's bank statements, plus documentation for current investments. I get rid of information about older investments after they have been closed 6 months. I should add that this is because I am easily confused!!
Bills - I keep the last year's bills, but no more than that. They are useful if you need to prove identity etc. and you do need the customer number details etc. to contact the companies in the event of problems. The older ones get shredded.
Car - I keep a record of all MOTs and service history, because those things are useful, plus all documentation to do with buying the car in the first place.
Receipts - I keep receipts in a box for things I could return or claim for, i.e. anything in warranty, and for anything large that might be out of warranty but where I might still need to make a claim that it ought to have lasted longer. I clip them to the instruction booklets for each thing so I can find them both together. Everything else gets binned.
I also have a bunch of documentation in the loft. This is really there only as a backup. I used to get rid of bank statements and pay slips after 3 years, but an older colleague had to produce all of hers (which she had fortunately kept) to prove her pension contributions when someone screwed up administratively. And I do mean ALL of them! So we now keep all of these, filed by date. Only the last year's are in the house - the rest are in the loft and I transfer a pile over to the filing box up there once a year. It's a bit of a pain, but having seen what my colleague went through, I think it's worth it.