Every now and then you come across a tool that is just so fundamentally useful that you'd have to have rocks in your head if you didn't use it- Red Gate SQL Compare is one such tool.
Since starting Kognition I've become a firm believer in the concept that a well organised change management process is good for business (reduces support costs), good for the customer (reduces errors) and most importantly good for developer sanity.
We use a Dev->Staging->Production lifecycle. This is reasonably easy to manage for application code but databases are always the bugbear.
SQL Compare makes managing the migration of databases changes through the various lifecylce stages. Basically it allows you to compare and then merge the changes in SQL server databases. A simple concept but their execution is really good.
If you are an enterprise or an enterprise developer then you really should be using this bit of kit. If you are doing dev->staging->production migrations by hand then it will save you a huge amount of time. If you are not doing the migrations at all (and do all your work on production databases) then you are insane.
Oh... BTW: The person to thank for our impecable Change management is our CTO @ Kognition Mr Nick Head.... really smart process oriented cookie.