The following screen capture shows the dilema of entering text in colums. The dialog displays text in a proportional font instead of the selected font. (BTW - this also shows the need for "tables" - if the idea does't already exist, i'll add it.)
Text should be editable directly in Layout. Text entry dialog box is a typical example of primitive tools used in the Late Computer Stone Age which have unfortunately persisted into modern times of ArcGIS.
If I have columns of text I always end up typing it out in a decent text editor (e.g. PSPad) first and then cut & pasting it into ArcMap. It seems that Arc 10 has a new lick of paint on the outside, but a lot of the functionality is still pretty ancient.