tables with lots of columns

I have a table that lists various attributes of an individuals personal development plan; objective, time to complete objective, comments etc. The table is editable so the user can directly add comments without having to go to an intermediate form. The problem is that the client wants to add more columns and this is messing up the visual display.

The alternatives I have are:

  1. allowing columns to expand out on click
  2. keeping essential attributes in table, rest in 'advanced edit option form' or somesuch
  3. I don't know - have you any ideas?

One more thing to add: I think the addition of extra columns is based on user feedback ...

edit: here is what I have gone for table with expandable columns