Most efficient way to run update query

SQL Apprentice Question
Hi all,
Any thoughts on the best way to run an update query to update a specific
list of records where all records get updated to same thing. I would think
a temp table to hold the list would be best but am also looking at the
easiest for an end user to run. The list of items is over 7000
Example:
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS' where item_no = '001-LBK'
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS' where item_no = '001-LYE'
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS' where item_no = '001-XLBK'
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS' where item_no = '001-XLYE'
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS' where item_no = '002-LGR'
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS' where item_no = '002-LRE'

All records get set to same. I tried using an IN list but this was
significantly slower:
update imitmidx_sql set activity_cd = 'O', activity_dt = '20060601',
prod_cat = 'OBS'
where item_no in
('001-LBK',
'001-LYE',
'001-XLBK',
'001-XLYE',
'002-LGR',
'002-LRE')



Celko Answers
Put the working data into a working table with an index on it and try
this:

UPDATE Imitmidx
SET activity_cd = 'O',
activity_dt = '2006-06-01',
prod_cat = 'OBS'
WHERE item_no
IN (SELECT item_no FROM WorkingData);


You can also add constraints for data scrubbing to WorkingData.