If you can't ride without blocking cars during rush hour, I would emphatically say, DON'T DO IT!
People get very tense on the way to work, and consistently blocking commuters invites road rage. When I was in my 20s I rode my bike to work in Washington D.C., mostly down Connecticut Avenue. On the way to work it was mostly down hill and I didn't hold people up because I was riding fast. On the way home I rode - and this is the way I always ride on a busy street - as far to the right as possible (watching out for doors opening from parked cars). Whenever I ride on a busy street I don't take the entire lane that I am legally entitled to. I ride as far to the right as possible, hugging or staying to the right of the white line. I remain aware of cars behind me, and if I create a slow parade of more than 2 or 3 cars I will pull over and let people pass.
I have very rarely almost gotten into fights with stopped cars, but I hope I am never stupid enough to pick a fight with a moving car.
And my reply to those pointing out that cyclists legally are entitled to the road and the entire lane, I do not want my tombstone inscribed with, "I had the right of way"