A little history on the "not bumping"... I had set it up to not bump when we were at our busiest and often getting about 40 new threads a day. Bumping meant that your post could fall off the board very very quickly.
I personally perfer not bumping as I have set my preferences up to just read one message at a time (instead of the whole thread) and then I can easily see what I have read by looking at the "new". It also gives me an idea of what order things were posted in which sometimes is important.
Having said that, I can function with it either way.
Monica (mom to 9 year old Mikey and in the process of adopting number 2)