Displaying and editing complex data

Question

I need to display large amount of data per each record, and perhaps edit it. I thought maybe displaying data that is most stable in table rows with an additional side panel for additional data, like in this sketch:

Here is how an inline adding of a row might look like:

Another idea is not to display additional data at once, but to leave it for viewing/editing in a modal window like this:

What is the proper balance for reducing the number of clicks the user has to make and not overcrowding the UI, and how to accomplish that for complex data records?

Answer 1

I've always liked the way MS Money offers to edit the records:

Using an inline form, and expanding the row for making more room to easy edit.
BUT the implementation in key. They have put ton of details to make it work perfectly with several hotkey, common key (like Enter), clicks combinations, etc.

Answer 2

If most of the rows need to be updated/filled most of the time, you would better go with the in-line design. However, if only a certain row is to be chosen for edit, then you could present a modal dialog.