I think this decade was a good year for film: Gladiator, LOTR series, Slumdog Millionare, Avatar, etc.
As for music, the only major change was that Rock was knocked from its perch by hip/hop and rap. No new innovative sounds really in my opinion though. That is up for possible debate I guess but whatever.
I wont even get into how shit the majority of TV has been this decade really. There have been some standout shows but they have been eclipsed by all the junk.
I think games have taken one of the biggest steps this decade. Graphics, storytelling, and gameplay mechanics have all made major progress and this industry has exploded into something to rival TV and movies.
As for tech, iPod, iPhone(and most cellphones), raw computing power progress, battery life, internet and internet speeds, GPS navigation, and much much more. Tech and gadgets have definitely made the biggest impact on this decade in the entertainment industry. They have changed the way the majority of the modern world live their everyday lives.