Getting Ready to do Something you Might Regret?
If you're mucking around in your database, and need to save your changes in a transactionally safe manner, but JUST might want to leave a flag or some kind of marker that would let you know what you need to return to should you later on decide it was a bad idea, then SQL Server has you covered:
BEGIN TRAN PrePlunge
WITH MARK 'Prior to Doing Stuff I might Regret'
Then, if you decide you need to undo your changes, you can always throw in the STOPATMARK clause as part of a RESTORE + RECOVERY. (Of course, ANY changes you've made SINCE that mark are toast, but it's still nice to have the option.)
Books Online covers this in a bit more detail, and it works with SQL Server 2000, 2005, and 2008.