I would definitely consider assigning large deletes to a large rollback segment.
Re: Halo's suggestion that you commit every x rows, I'm not sure how to efficiently do that, and there are reasons why you might want to ensure that the entire delete was done in one swipe. Autocommit does not work here. Autocommit commits every x number of statements, not every x number of records in a single DML operation.
If you had a table of two million rows, you would need a sizeable rollback segment to accomplish deleting this table all in one shot. Keep the RB segment offline except when you need it, and explicitly assign the delete transaction to it. The proper sizing of this rollback segment depends on how big a delete you're doing, but don't be too shy in sizing it at say initial 1M, next 1M, maxextents 200 because if the operation does blow out your rollback segment, the transaction will take an extra long time because the entire delete will have to be rolled back. The extra wait can be frustrating.
Re: Nologging suggestion. I'm not aware of this option being available for delete operations, but if I'm wrong, somebody please pipe up and let me know.

Johnny D.