Things that had me surprised with 10G Standard Edition
The following features not being supported by standard edition had me surprised(there are a lot more but this caught my attention)
1)Reorgs: Online index build, online table reorg/redef, online index coalesce. Global index maintenance during DDL
(some of the above we may overcome with third party LiveReorg Products)
2)Recovery: block level media recovery, Tablespace point in time recovery.
3)With 10g Std edition incremental backup and recovery is supported but not with 9i Std Edition - think of it which means you always have to do a full bkups.4)Indexes : Bitmap indexes are not supported while Function based indexes are supported in 10G Std edition.