I'm working on tweaking mine a bit. I'm an artist and graphic designer, so my situation is a little different. I'll be following this to see what other people say.

I'm a fellow IT wrangler and my system is quite close to yours. I use
- Moleskine for note taking in meetings
- 3x5 cards as a mobile capture and in-my-face reminder mechanism
- MyLifeOrganized to receive the data captured on the 3x5s and as the core of ,y trusted system

My contexts are close to yours as well, but I break them down further to get more granular and I split between Home and Work. You can take a look at some screenshots at http://www.flickr.com/photos/trandell/sets/72057594094707412. I use the GTD template developed by the fine people at MLO and tweaked it to fit my needs better.

IMHO MLO is fantastic. It is lightweight, nimble and super-intuitive. Perhaps kGTD/OmniOutliner is strong competition, but since I have a Mac at home and PC at work, MLO wins. Plus I can run MLO completely from a USB key, giving me added flexibility. Download the trial and give it a spin.

Hope this helps.

I have to handle a whole range of IT-related tasks as well, but I have tried to resist dividing up my context by activity because it leads to my old 'todo list for everything' approach. By keeping my contexts related to location, I can avoid worrying about a whole heap of things that are physically impossible for me to do (eg. because I need to be in a different building to do them). I find that, if I divide tasks up by activity, I tend to worry or feel guilty because in my head I keep saying, 'I could be doing X just now' or 'I should be doing Y just now'.

Its early days for me so I have no idea if this approach has any tangible benefits: its just feels a bit more intuitive.

That is a good approach. We are a small municipality and we have 3 main locations and 3 fire stations with one computer at each.

Of the three main locations, there is a police officer at the Public Safety building who handles most of their IT stuff, even though I am ultimately responsible. He his a good IT guy and has a good handle on the situation there.

At our other building, there are only 4 computers and one 'server' there. They are very low maintenence so I don't worry much there.

At my location, which is City Hall, there are 40 users and one all-in-one 10 year old Novell server. My main project now is transistioning the network from Novell to Windows, which will take the better course of a year to fully implement.

I really have one location to deal with so I decided to break it down the way I did. This will work even better after the transistion because I should be able to do any and all software support from my desk, and only go to the user's workstation when there is a hardware or peripheral issue.

Michael