how to quickly insert data as select In an Oracle DB have about 200M rows (about 20GB data) that I would like to insert into another table by  

insert into foo select * from bar where some_unimportant=condition;


How do I do that the fastest way if I can always drop the foo table and redo the insert in case of any problem? Like, I don't need to be able to do a rollback.
Since I can drop the foo table, I have complete control over its creation also, if there are some good options to use to speed up the insert.

Of course, after the inserts, I wish the table to behave as an ordinary table (support undo by using rollback, etc.)

UPDATE: The table was created as an IOT, so I guess that changes things. Should I run 

 alter index foo_pk nologging;


also?
Improving INSERT Performance with Direct-Path INSERT

Example:

alter table foo nologging;
alter session force parallel query parallel 8;
alter session force parallel dml parallel 8;
insert /*+ append */ into foo select * from bar where some_unimportant=condition;