I have noticed that Blender 2.49 had a way of "remembering" the last-used parameters within a session. Each tool, regardless of when last used, so long as the current session is still active. "Select Random Vertices" would remember that you chose "28%" and present it to you again... not quite so important as it has only one parameter. More importantly though, tools with multiple parameters to set were much easier to use when you could set them once and forget them.

Under 2.5 and later, the change with tools now being coded in Python has brought many good things, but this one detail is something that was lost somehow.