How do you file your receipts?

One of the many, many things on my big to do (or rather Teux Deux) list is "work out how the heck to file those precious receipts". The whole tax-deductible assault course ahead of me is rather daunting, and I want to make it as easy for myself as possible by getting a sensible, simple system in place to keep track of my expenses. I asked in twitter what other freelancers do, and got a rather varied response:

@bojkowski: Spike file. Seriously. Spike files are ace. Here's some nice ones …
@studio_creme: massive threading needle.
@WeMakeMags: I swear by a lever-arch file with plastic pockets divided into months. So there. Being VAT registered focuses the mind too!
@BecauseStudio: My elaborate filing system:
@Fountainjohn: Plastic see-through sleeve stuffed behind computer. Inside - balls of fluff wrapped with petrol bills, and bills from Rymans.
@edwardlamb: A4 envelope! … and Excel spreadsheet (with note saying whether it was paid for personally or through business account).
@lukejonesme: I document the expense in FreeAgent and put them in one of those accordion file things along with anything else.
@ein_ah: mine isn't much more organised. The monkey keeps me from throwing everything in the top drawer!
@DavidHAllison: I have a 2 tier system: 1. Leave on desk on big pile for at least 3 mths 2. Then throw guiltily in no order into box file. GENIUS!
@bluerocket: shoebox.

It seems there are as many methods as there are freelancers! I rather like the spike file/needle idea – it's the kind of organised chaos I like, and a black one would look daahling on my desk alongside House Bird and the ol' Anglepoise (although I fear it would contribute to the new paranoia I've developed since working at home on my own: everything, absolutely everything, looks like a potential Final Desitination/Mousetrap deathrap-in-waiting … having a massive impaly spike on my desk is just going to put me into a constant state of anxiety).

So, how do you file your receipts?