I have two major problems with Workrave, which would otherwise be exactly what I want:

1. If you aren't using keyboard or mouse constantly, you end up with longer intervals between breaks.
2. There is no simple way to disable/reenable it. Bug 501 is 6 years old.
3. It would be even better if it could automatically be disabled when using specific applications (e.g., as mentioned in the bug, full-screen games).

Yes, it's open source, but it's C++, so I won't be able to just modify it :( Are there good alternatives?

@IainB:
I knew about Word's AutoText, but it doesn't really do what I need:

You can then type in the part-words you want to be auto-corrected (or auto-completed) and the full string/phrase that you want it to become

With most text editors, you don't need to specifically tell it to autocomplete this or that word: if you start typing "syn" and there are already words "syncronous" and "synchronicity" in the file, it should automatically propose completion to "syncron" (and possibly a way to choose between "syncronous" and "synchronicity" as well). Strangely, LibreOffice does it wrong: it will propose whichever of "syncronous" and "synchronicity" is more common instead of the common prefix.
@cmpm:
Thanks, I'll try it out!

So I changed all of my boxes to use Win + Alt + Space.

-phitsc

Thanks for the idea! Just switched to it from Ctrl+Shift+Space. (I used to use Win+Space on XP/Vista as well and abandoned it for the same reason.)