I see the problem as being one some History professors refer to when they remind students to consider that life is remembered backwards but it is lived forwards. A good tool would have the flexibility to adjust previously defined activities dynamically as events unfold. Yes, last week I blocked Tuesday afternoon to writeup a test plan but the phone rang and things changed and that single activity 4 hour block ends up being completed in 5 chunks over three days. The UX should be easy to break that work plan up but it isn't and I certainly don't want 5 tasks for this little thing anyway. Likewise, as a result the journaling of that time as it actually happened is lost along with the ability to gain useful metrics except at a less granular level.

Also, for what its worth I'm not sure about the 'i' thing or why u felt the need for a throwaway in this case, but it would be interesting to hear what tools you do use after trial and error.