I work in a Technical Support group and often I have to review error/activity logs written to database tables. Our clients have sites all over the world and it gets confusing to constantly convert time entries between my local time and the client sites' local times (which can span multiple time zones for a single implementation). UTC time (also called Zulu time) gives us a uniform way to compare log entries across multiple time zones.
Another nice benefit is that you don't have to worry about accounting for Daylight Savings Time changes (which vary from state to state, country to country, and from legislative whims).
Another big question, is whether to run the servers on the GMT time zone so that Sql error logs, Event logs, etc. are stamped UTC time.
Here is a useful Wikipedia link on UTC time:
http://en.wikipedia.org/wiki/Coordinated_Universal_Time