I just started the GTD process, and found GTDTW very soon after I started the process, so I’m using it exclusively to manage my life right now. I have a USB key (with thumbprint scanner built in, a bit of overkill, but cool nonetheless) with GTDTW and portable firefox on it. I’m going to be installing Essential PIM for keeping track of contacts, though right now, my contacts go into my ipod.

I also wish there was a server side component, and have toyed with expanding it using XMLHTTPRequest in javascript to call back and load the data sections in the file. All in all I really enjoy using GTDTW, and even use it to print out index cards for keeping on me (right now, just shopping lists, etc)