Interesting debate on bicycle lanes in Portland, actually a response to another article, which places the blame of several cyclist deaths on a combination of laws which require cyclists to unsafely position themselves at intersections.
I won't go into detail about the specific issues, some Oregon-law specific. Suffice it to say, it's often safest to ignore the law and use common sense. Don't pass vehicles on the right side, especially at intersections, is rule #1. (This is the corollary of "pretend you're invisible".)
Speaking of bicycle lanes, there's of course a number of problematic areas in Seattle where it's really not safe to use that lane, especially at intersections. One is a lane going northbound on to University Bridge where some unfortunate cyclist was plowed under by a truck turning right. (See rule #1.) Since there's two lanes of traffic going downhill, position yourself in the middle of the right lane, not bicycle lane, and so traffic turning right would have to either pass in front of you or stay behind.
Rule #2 is avoid bicycle lanes where you can get hit by a car door. Seattle has a few "door prize" lanes. Remember kids: On street parking is not only an automobile subsidy, it can kill you too.
Rule #3 is avoid bicycle lanes that continue on to nowhere. The intersection south on Greenlake Way intersecting NE 50th Street has a single bicycle lane which seemingly projects off to Kidd Valley, and through that intersection is no space for a cyclist with the adjacent traffic lane. Rather than negotiate a tricky merge, just take the second lane, which disappears in 100 feet or so and becomes a bike lane.