For me a whole lot depends on what I'm riding. For one bike (the one and only skinny tire road bike I own, an old 10-speed) I will avoid and go around just about anything larger then a small crack in the pavement. For another bike I will knowingly ride through just about anything including potholes that are three feet in diameter and a foot deep in the middle rather then go around.

I actually got an interesting comment from another cyclist one day about this. On that day my usual "bus bike" was in the shop being worked on so I took my "All Terrain" bike which is part mountain bike, part down-hill bike, and part urban fat-tire bike instead and while riding around town after taking the bus between towns with the bike in the rack on the bus I was making my way through traffic in town just doing my thing and handling the road chuck-holes and such as I saw best considering the bike I was riding and another cyclist who was in the lane behind me and eventually passed me hollered at me that I was riding my bike "Dodge Ram" style and by the tone of his voice he obviously thought I was crazy. I caught back up with him at a red light and asked him what he meant by this and he explained that drivers that drive Dodge Ram pickup trucks do not go around obstructions but rather go through them and do not slow down before going through them but actually accelerate slightly before going through the obstruction. I apparently though I was doing the same sort of thing with all the potholes and such and not ever changing my line and just going straight through everything and even accelerating before I hit them. I responded that I was actually trying to take the weight off me front tire up as I hit each pot-hole which meant jamming into the pedals and pulling up on the bars not enough to make the front tire loose road contact but enough to take almost all the weight off of it as I hit the potholes and keep me rear off of the seat when the rear wheel went through the pot-hole. He responded that he still though I had a "Dodge Ram" driving attitude and then the light changed.

So, I would have to say it depends on what I'm riding and if I know I can get away with going through obstacle because my bike can take the punishment then I will do so and I only go around stuff that I don't think my bike can take.