I think a lot of people are missing one of the biggest pains out of the DST change, which is meetings booked in an exchange environment. Even if you do everything Microsoft/RIM recommend, and do them within hours of each other (a very daunting task for any enterprise sized environment,) you will still have meetings off by an hour.
This can be caused by lots of reasons. If one desktop recieves the patch and sends a meeting to another user, who has not received the patch, the meeting time will be wrong. Even if you manage your DST updates flawlessly within your environment, and don't have any misplaced meetings, you have no control over any external sources that may be booking meetings with your users. It's pretty inconceivable that everyone will update at the same time.
I really don't want to be the one on the CEO's warpath the first time he shows up for a meeting early/late. These issues can be partly resolved by user education, but as another poster mentioned, it is very easy to get confused when talking about timezones. I've been working on our DST project, and I still need to think carefully every time I discuss the ramifications.
I think
Cnet had it right when they wrote that users should add this to their signature:
'Please note, if I (am) an hour late or an hour early for my meeting with you, please understand, its not my fault, it's my government.'