I always stop at red lights. Why wouldn't you? When I was a lot younger I didn't always, until a serious collision with a bus knocked some sense into me. Sure it's a pain to lose all that hard-won momentum, but two or three strokes of the pedals and you're quickly back up to speed.
Running red lights is a very common and very bad advertisement for cyclists. Thoughtless acts by a few of us give us all a bad name. There are plenty of excuses offered for running red lights, but I'm yet to come across a good one. It endangers your safety and the safety of other road users and pisses people off when we need all the friends we can get. If you run red lights on your bike, you're a dickhead. If you do it in front of me, you'll get an earful - like a couple of people in Hobart have in the last few weeks.
There have been a couple of pushes lately to make cyclists more conscious of the road rules. I like the Stop at Red campaign. Give it some thought.
Bonus link: the top 10 books about cycling.
5,936km so far this year.