to log or not to log

In summary :-
If nologging is specified on a table or tablespace all operations against a table will still be logged except

Alter table...move partition
alter table...split partition
alter index...split partition
alter index...rebuild
alter index...rebuild partition
create table...as select (CTAS)
create index
direct load with SQL*Loader
direct load INSERT (using APPEND)

with nologging specified


http://www.dbasupport.com/oracle/ora10g/managing_tables.shtml