The BigLig Thinks

I keep trying to use GTD in my daily life, but I do find it hard - perhaps because I'm too overloaded, although more likely I'm just not doing it right. But here's my current implementation. It's half electronic, half paper - every time I try using software to keep my lists I eventually give up and get back to index cards.
Capture
I have a cheap Buxton index card holder (like a Levenger pocket briefcase, only 10% of the price!) that carries blue index cards (blue cards=capture), and a Pilot G-2 (violet ink, of course!) that goes in my pocket or bag. I got the card holder in a supermarket in New Jersey - I've never seen a UK stationary supplier stock anything like it. A pity, since I'd really like to get something bigger that held index cards in the same way, but also had a pen loop and credit card slots so I could use it as a wallet. Then I'd be sure to always have it with me. Levenger do one, of course, but not cheap, especially when you factor in shipping.
A stack of blue cards and pens sits on my desk for customer walk-ins, phone calls, or random ideas.
I also have a Blackberry Bold that I can use for capture if I need to capture a photo or if I run out of cards, by emailing myself.
Inboxes
I have three. A physical tray on my desk, my work inbox, and all the items in my work ticketing system that are in "assigned" state.
There are some other places that I check occasionally and move what I find there into the physical tray.
Lists
I have an standard plastic index card box with section dividers for Next Actions, Projects, waiting on/agenda, and someday/maybe. I also have a smaller box for travelling.
I use color coded cards here too. Red is next actions; yellow is projects and someday maybe (things fluidly move between the two categories) and green is waiting on/agenda. The yellow cards get ticket numbers written on them when they represent a ticket in "working on" state. The green cards get the name of the person or meeting. If I have multiple items against a person they share a card so it's easier to cover everything, but red and yellow cards get one idea per card.
You'll notice I don't use contexts - turns out all my work is in the same context, so really it's just one big context (@working, I suppose).
I hit upon a neat way to associate a next action with the project it's part of - I use a paperclip to pin the yellow behind the red. Sometimes multiple yellows, as often I need to do one action to move forward on several projects. Sometimes I clip the yellow behind a green because the project is stalled waiting on someone. On the occasions where I have multiple actions on a project, I just pin all the reds in front of the yellow.
Calendar
I use Outlook's calendar, synced to my blackberry
Other stuff
Project support materials - if there's paper (rare), it goes in a manilla file in a holder on my desk. If it's electronic, it goes on my desktop (I use stardock's fences to group by project - great little bit of software) Old material goes in a file drawer, or in a zip file on the server.
Reference material is kept in evernote, synced to the cloud and hence my blackberry (roll on the proper evernote client for blackberry, but the web client is adequate)
My "to read" pile goes on the holder for the manilla files, since it's always empty.
I have a stack of out of date plain pads I use for scratch paper. Anything I need to keep goes into the inbox
Lastly, I keep two plastic folders; the a4 one is used for that old David Allen trick of dealing with interruptions by sweeping everything on your desk into a folder, and the a5 one is used to collect receipts etc. when travelling.