This is my approach to @Work...
I have only 2 List in reference with my work, @Work and @WorkComputer
In the first goes everything that imply job, and can only or need to be done at work, fax, call, email, write, review, send, anything that I need to do at work, in my workstation or with work tools or is better if I am at my workstation.
My @WorkComputer, is the list that require Connection to the Work Network, since I am not able to do it from home, for me that required be there, things that need that goes there, other computer things goes in my computer list, because can be done, at work, at home, at the cafe, or any other place with the laptop.
I use to have that problem, I think was listening to GTD Fast! where I understand that my Work goes @Work, my calls maybe can contain Work related, but then do not need me to be at the office, for example if I have something to talk to my Boss, that goes into @Work List, because the issues on the agenda generally require me to be at work.
I understand this make the @work list get bigger, but I know exactly what is my work.
If I get idle or tired, then I change to other lists, that can be done at work but not necesary are work, for example, call Joe (Other department person at work) to define business trip... In this case this iten is in my actual @call list, but in order to define the things I do not need to be at work, I can do it in traffic (I live in LA, therefore that is a big part of my day) or at home, or anywhere else, then is in my @Calls list.
I hope this helps