As long as there's room, no ridiculously large truck in front of me (and no dangerous sewer grates), I will filter (a large truck is probably a deal-breaker). Filtering is the easy part. The trick is having a plan for what to do when you get to the front. The ideal thing is having room to share a lane as you go through the intersection (or expecting to be able to merge into traffic). Sharing absolutely requires that whoever you're sharing with knows you're there, so they won't right-hook you. This generally means you have to get in front of them before the light changes. And make sure they see you! I'm definately not going to pass anybody as we're going through the intersection. If there's a constriction on the far side of the intersection, making lane-sharing impossible at that point, I generally have some choice names to call the designer who put it there but, if I'm properly positioned in front of a break in traffic, even such a stupid design is not necessarily a deal-breaker. I don't ever recall walking a bicycle across an intersection when I didn't have a mechanical problem or a flat tire. In some instances I may ride across an intersection in a crosswalk (oh, the horror of it!).

But that's just me.

Whatever you do, the two most important things that will keep you out of trouble are situational awareness and bike-handling skills. Experience is nice, too.

Addendum: despite the fact that the dangers of 'bicyclist-killer' sewer grates have been known for decades, they do still exist. I've even seen new ones being installed (although, after complaints, they were turned the other way, so the openings were perpendicular to the direction of travel and not parallel to it). Potholes also exist. Be careful out there.